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THE  ELEMENTS 


OF 


RAILROAD  ENGINEERING 


Prepared  for  Students  of 

The  International  Correspondence  Schools 

SCRANTON,  PA. 


Volume  II 


SURVEYING  RAILROAD  LOCATION 

LAND  SURVEYING        RAILROAD  CONSTRUCTION 
MAPPING  TRACK  WORK 

RAILROAD  STRUCTURES 

WITH  PRACTICAL  QIJESTIONS  AND  EXAMPLES 


First  Edition 


SCRANTON 

THE  COLLIERY  ENGINEER  CO. 
1897 

967 


V.  ^ 


)   I  /.  t  I  M 


Copyright,  1897,  by  The  Colliery  Engineer  Company. 


Surveying :    Copyright,  1895,  by  The  Colliery  ENGINEER  Company. 
Land  Surveying  :    Copyright,  1895,  by  The  Colliery  Engineer  Company. 
Mapping  :    Copyright,  18i)5,  by  The  Colliery  Engineer  Company. 
Railroad  Location  :    Copyright,  1895,  by  The  COLLIERY  ENGINEER  Company. 
Railroad  Construction  :    Copyright,  1895,  by  The  COLLIERY  ENGINEER  Company. 
Track  Work  :    Copyright,  1896,  by  The  COLLIERY  ENGINEER  COMPANY. 
Railroad  Structures  :    Copyright,  1896,  by  The  COLLIERY  Engineer  Company. 


BURR  PRINTING  HOUSE, 

FRANKFORT  AND  JACOB  STREETS, 

NEW  YORK. 


CONTENTS. 


Surveying.  page 

Geometrical  Principles, GOl 

Compass  Surveying, 605 

Transit  Surveying,          - (J2l 

Triangulation,         -         - 634 

Curves,    -         -         -         - 639 

Leveling, 655 

Topographical  Surveying,       -         -         .         .         .  673 

Indirect  Leveling,  -         -  • 682 

Hydrographic  Surveying, 690 

Land  Surveying. 

United  States  System,    -         -         -         -         .         _  693 

Areas, 714 

Latitudes  and  Departures, 717 

Town  Sites  and  Subdivisions,         -         .         .         .  733 

Mapping. 

Introduction,  - 74I 

Platting  Angles, 74I,  748 

Map  of  Railroad  Location, 766 

Topographical  Drawing, 776 

Contours  and  Slopes,      -         .         .         ...  779 

Conventional  Signs, 739 

Topographical  Maps, 792 

Map  of  Village, 799 

Railroad  Location. 

Introduction, .  313 

Reconnaissance,  <J> 8I5 


157140 


iv  CONTENTS. 

Railroad  Location — continued.  page 

Field  Work, 823 

Problems  in  Location,    -..-..  832 

Specifications  for  Grading  and  Bridging,        -         -  800 

Railroad  Construction. 

The  Engineer  Corps,    .....         -         -  869 

Cross-Sectioning,           ......  870 

Culverts, -        -        -  878 

Retaining  Walls,  - 899 

Excavation,  -         - 912 

Tunnel  Work, 935 

Protection  Work, 966 

Routine  Work, 970 

Bridge  Work,         -....-.  978 

Pile  Work, 1002 

Estimates, 1017 

Track  Work. 

Track  Laying, 1029 

Track  Joints, 1036 

Rails, 1038 

Expansion  and  Contraction,          ....  1043 

Spiking  Rails, 1045 

Surfacing  Track, 1048 

Drainage, 1052 

Care  and  Maintenance  of  Track,           .         .         .  1058 

Curved  Track, 1087 

Frogs  and  Switches, 1102 

Yards  and  Terminals, 1145 

General  Instructions,    .                  ....  1148 

Railroad  Structures. 

Wooden  Trestles, 1103 

Framed  Bents, 1177 

Floor  System, 1186 

Bracing,  ' 1195 

Iron  Details, -         -  1198 


CONTENTS.  V 

Railroad  Structures — cotitinued. 

Connection  of  Trestle  with  Embankment — Pro-  page 

tection  Against  Accidents,         -         -         -         .  1207 

Field  Engineering  and  Erecting,           -         -         -  1211 

vSpecifications  for  Wooden  Trestles,      ...  1213 

Bills  of  Materials,  Records,  and  Maintenance,     -  1334 

Standard  Trestle  Plans, 1230 

Simple  Wooden  Truss  Bridges,     -         -         -         -  1246 

Water  Stations,     -         -         -         -         -         -         -  1374 

Coaling  Stations, 1381 

Turntables, 1385 

Questions  and  Examples. 

Surveying,         -         -         -     Questions       014-705  1397 

Land  Surveying,       -         -     Questions       706-755  1309 

Railroad  Location,    -         -     Questions       756-813  1315 

Railroad  Construction,      -     Questions       813-873  1331 

Railroad  Construction,      -     Questions       873-946  1337 

Track  Work,     -         -         -     Questions     947-1016  1333 

Railroad  Structures,          -     Questions  1017-1083  1339 


SURVEYING. 


GEOMETRY. 

1 180.  If  two  triangles  have  two  sides  and  the  included 
angle  of  the  one  equal  to  two  sides  and  the  included  angle 
of  the  other,  the  triangles  are 
equal  in  all  their  parts.  Thus, 
in  the  two  triangles  ABC 
and  D  E  F,  Fig.  236,  if  the 
side  A  B  is  equal  to  the  side 

D  E  ;  the  side  B  C  to  the  side  ^        \ ^  ^  p 

E F,  and  the  angle  B  to  the  fig.  236. 

angle  E,  the  triangles  are  equal  in  every  respect. 

1181.  If  a  straight  line,  A  B,  Fig.  237,  intersects  two 
parallel  straight  lines,  C  D  and  E  F,  it  is  called  a  secant 

with  respect  to  them,  and  the  eight 
angles  formed  about  the  points  of  in- 
tersection have  different  names  applied 
to  them  with  respect  to  each  other,  as 
follows : 

First — Interior     angles     on    the 

same  side  are  those  which  lie  on  the 

Fig.  237,  same  side  of  the  secant  and  within  the 

other  two  lines.     Thus,  in  Fig.  237,  H  G  D  2Lnd  G  H  F  2ive 

interior  angles  on  the  same  side. 

Second — Exterior  angles  on  the  same  side  are  those 
which  lie  on  the  same  side  of  the  secant  but  ivithout  the 
other  two  lines.  Thus,  A  G  D  a^nd  F  H  B  2Lxe  exterior 
angles  on  the  same  side. 

Third — Alternate  interior  angles  are  those  which  lie 
on  opposite  sides  of  the  secant  and  within  the  other  two 
lines.     Thus,  C  G  H and  G  H  Fare  alternate  interior  angles. 


602 


SURVEYING. 


Fourth — Alternate  exterior  uncles  are  those  which 
lie  on  opposite  sides  of  the  secant  and  without  the  other  two 
lines.     Thus,  A  G  C  and  F H B2^x%  alternate  exterior  angles. 

Fifth — Opposite   exterior   and   interior  antcles  are 

those  which  lie  on  the  same  side  of  the  secant,  the  one  within 
and  the  other  without  the  other  two  lines.  Thus,  A  G  D 
and  G  H  F  are  opposite  exterior  and  interior  angles. 

1182.  If  a  straight  line  intersects  two  parallel  lines, 
the  sum  of  the  interior  angles  on  the  same  side  is  equal  to 
two  right  angles,  and  the  sum  of  the  exterior  angles  on  the 
same  side  is  also  equal  to  two  right  angles.  Thus,  in  Fig. 
237,  the  interior  angles  D  G  H  and  F  H  G  are  together 
equal  to  two  right  angles,  and  the  exterior  angles  D  G  A 
and  F  H  B  are  together  equal  to  two  right  angles. 

1183.  If  a  line  intersects  two  parallel  straight  lines, 
the  alternate  interior  angles  are  equal  to  each  other,  and 
the  alternate  exterior  angles  are  also  equal  to  each  other. 
Thus,  in  Fig.  237,  the  angle  C  G  H  \s  equal  to  F  H  G,  and 
angle  C  G  A  \?,  equal  to  F  H  B. 

1184.  The  complement  of  an  angle  is  the  difference 


E 


B 

FlO.  238. 


between  that  angle  and  a  right  angle. 
Thus,  in  Fig.  238,  A  B  E  is  the  comple- 
ment oi  D  B  E. 

-D      1185.     The     supplement     of     an 

angle  is  the  difference  between  that 
angle  and  two  right  angles.  Thus,  C  B  E  is  the  supplement 
oiDB  E. 

1 186.  In  any  triangle,  a  line  drawn 
parallel  to  one  of  the  sides  divides  the 
other  sides  proportionally.  Thus,  in  the 
triangle  ABC,  Fig.  239,  the  line  D  E 
drawn  parallel  to  B  C  divides  the  sides 
A  B  and  A  C  proportionally  ;  that  is, 

A  B  \  A  D\\  A  C  \  A  E; 

A  D  '.  D  B\:  A  E  :  E  C,  and 

A  B  :  D  B  ::  A  C  :  E  C.  KiG.a:>i.. 


SURVEYING.  603 

« 

1 1 87.  Polygons  are  similar  when  they  are  mutually 

equiangular  and  have  their  homologous  sides  proportional. 

In  similar  polygons,  any  points,  lines,  or  angles  similarly 
situated  in  each  are  called  homologous.  The  ratio  of  a 
side  of  one  polygon  to  its  homologous  side  in  another  is 
called  the  ratio  of  similitude  of  the  polygons. 

1188.  Triangles  which  are  mutually  equiangular  are 
similar,  and  their  areas  are  to  each  other  as  the  squares  of 
their  homologous  sides. 

Thus,  in  the  triangles 
A  B  C  ?ind.D  E  F,  Fig.  240, 
if  the  angle  A  is  equal  to  the 
angle  D\  the  angle  B  to  the 

angle  E,  and  the  angle  C  to  B^ ^CE^ ^F 

the  angle  F,  the  triangles  are  Fig.  24o. 

similar,  and  their  areas  are  to  each  other  as  the  squares  of 

their  homologous  sides. 

For  example,  if  B  C  =  ^0  feet,   EF=oO  feet,   and   the 
area  of  the  triangle  A  B  C  =  1,G00  sq.  ft.,  then 
80*  :   50'  ::  1,600  :  area  oi  D  E  F,  or 
6,400  :  2,500  ::  1,600  :  625  sq.  ft. 
Hence,  area  oi  D  E  Fis  625  sq.  ft. 

1 1 89.  The  areas  of  similar  polygons  are  to  each  other 
as  the  squares  of  their  homologous  sides. 

Thus,  if  the  area  of  a  regular  hexagon  with  a  side  of  10 
inches  is  259.809  sq.  in.,  the  area  of  a  similar  hexagon  whose 
side  is  15  inches  may  be  found  as  follows: 

10"  :  15''  ::  259.809  :  area  required,  or 
100  :  225  ::  259.809  :  584.57  sq.  in. 

1190.  The  circumferences  of  circles  are  to  each  other 
as  their  diameters,  and  their  areas  are  to  each  other  as  the 
squares  of  their  diameters. 

Thus,  if  the  circumference  of  a  circle  12  inches  in  diam- 
eter is  37.7  inches,  the  circumference  of  a  circle  of  18  inches 
diameter  may  be  found  by  proportion.     Thus, 

12  :  18  ::  37.7  :  56.55  in.,  the  circumference  required. 


G04 


SURVEYING. 


Again,  if  the  area  of  a  circle  of  12  inches  diameter  is 
113.098  sq.  in.,  the  area  of  a  circle  of  18  inches  diameter 
may  be  found  as  follows: 

12'  :  18'  ::  113.098  :  area  required,  or 
144  :  324  ::  113.098  :,  254.47  sq.  in. 

1191.  An  angle  formed  by  a  tangent  and  a  chord 
meeting  at  the  point  of  contact  is 
measured  by  half  the  included  arc. 

Thus,  in  Fig.  241,  the  angle  A  C  D 
formed  by  the  meeting  of  the  tangent 
A  B  and  the  chord  C  D  '\s  measured 
by  half  the  arc  C  E  D.  Similarly,  the 
angle  B  C  D  \s  measured  by  half  the 
arc  C  D. 

1192.  Two  tangents  to  a  circle  drawn  from  any  point 
are  equal,  and  if  a  chord  be  drawn  joining 
these  tangent  points,  the  angles  between 
the  chord  and  the  tangents  are  equal. 

Thus,  in  Fig.  242,  the  two  tangents 
A  B  and  A  C  drawn  to  the  circle  from 
the  point  A  are  equal,  and  the  angles 
ABC  and  A  C  B,  formed  by  the  chord 
and  tangents,  are  equal  to  each  other. 

1 1 93.  In  similar  circles  equal  chords 
subtend  equal  angles  at  the  center  and 
also  at  the  circumference.  fig.  242. 

Thus,  in  Fig.  243,  the  angles  A  O  B,  B  O  C,  2.nA  C  O  D 
subtended  by  the  equal  chords  A  B, 
B  C,  and  C  D  are  equal  to  each 
other. 

Again,  the  angles  B  A  C  and 
CAD  are  also  equal  to  each 
other. 

1194.     In  Fig 
be    any   triangle, 
sides,    as   A    C,    is 


Fig.  243. 


244,  let  A  B  C 
If    one   of    the 
prolonged,    the 
angle  BCD-  included  between  the 


SURVEYING. 


605 


side  thus  prolonged  and  the  other  side  B  C  of  the  triangle, 
which  meets  A  C  a.t  C,  is  called  an 
exterior  angle.  The  two  remain- 
ing angles  A  and  B  of  the  triangle, 
which  are  opposite  to  the  angle  6', 
are  called  opposite  interior 
angles.  In  any  triangle,  an  ex- 
terior angle  is  equal  to  the  sum  of 
the  two  opposite  interior  angles ;  that  ^"^-  "^^• 

is,  in  the  above  figure,  the  exterior  angle  B  C  D  is  equal  to 
the  sum  of  the  two  opposite  interior  angles,  A  and  B. 

1 195.     Problem. — Having  given  one  of  the  angles  of  a 
triangle,  one  of  the  including  sides,  and  the  difference  of 
^  the  other  two  sides,  to  construct 

it. 

Let  C,  Fig.  245,  be  the  given 

angle,  A  the  given  side,  and  B 

the  difference  of  the  other  sides. 

Draw  D  E  equal    to    the  given 

side  A\    2X  D   make    the  angle 

E  D  F  equal  to  the  given  angle  (7; 

Fig.  245.  on  D  F  lay  oK  D  G  equal  to  the 

given  difference  B.     Join  E  G.     At  the  middle  point  //  of 

E  G  erect  a  perpendicular  cutting  D  Fin  K.     Draw  K  E. 

D  E  K  is  the  required  triangle. 


COMPASS    SURVEYING. 

1196.     The    Compass. — The   surveyor's   compass 

consists  of  the  magnetic  needle,  the  case  in  which  it  is  en- 
closed, and  the  support  on  which  it  is  placed  when  ready  for 
use. 


1197.  The  Magnetic  Needle.— The  magnetic 
needle  is  a  slender  bar  of  steel,  five  or  six  inches  in  length, 
strongly  magnetized,  and  mounted  upon  a  finely  pointed 
pivot  on  which  it  freely  turns,  always  pointing  in  the  same 


006 


SURVEYING. 


direction,  viz. :  the  north  and  south  line,  or,  as  it  is  called, 
the  magnetic  meridian. 

1198.     North  and  South  Ends  of  Needle.— Owing 

to  the  earth's  attraction,  the  north  end  of  the  needle  dips, 

that  is,  it  is  drawn  downward  from  a  horizontal  position, 

while  the  south  end  is  correspondingly  raised.     To  prevent 

this   dipping,    several    coils   of   platinum    wire   are   wound 

_,,  ^.  „,.  around  the  south  end 

rPlattnum  Wire.  .    ,  ,,     ,        _. 

— ■  "^    of  the  needle  (see  Pig. 

246),  keeping  it  per- 
fectly balanced  upon 
its  pivot  and  permit- 
These  coils  of  wire  at 
the  north  end   and 


\Pivot. 


Fig.  246. 


ting  entire  freedom  of  movement 
once  indicate  to  the  observer  which  is 
which  is  the  south  end  of  the  needle. 


1199.,  The  Sights. — At  either  end  of  a  line  passing 
through  the  needle  pivot  is  a  sight,  which  consists  of  an 
upright  bar  of  brass    A  and  B.     (See  Fig.  247.)     Narrow 


Fig.  247. 


vertical  slits,  with  holes  at  their  top  and  bottom,  divide  this 
bar,  as  shown  at  C  and  D.  These  arrangements  enable 
the  observer  to  train  the  line  of  sight  upon  any  desired 
object. 


SURVEYING. 


607 


1 200.  The  Divided  Circle. — The  compass  box  con- 
tains a  graduated  circle  divided  to  half  degrees,  at  the 
center  of  which  is  the  pivot  supporting  the  needle.  The 
degrees  are  numbered  from  0°  to  90°  both  ways  from  the 
points  where  a  line  drawn  through  the  slits  would  cut  the 
circle. 

1201.  Lettering. — The  lettering  of  the  surveyor's 
compass  is  at  first  confusing  to  those  learning  its  use.  A 
person  standing  with  his  back  to  the  south  and  facing  the 
north  will  have  the  east  on  his  right  hand  and  the  west 
on  his  left.  These  latter  directions,  viz.,  the  east  and. 
the  west,  are  reversed  in  the  lettering  of  the  compass. 
The  reasons  for  this  apparent  error  are  explained  in  the 
following  figures: 


Fig.  248. 


Fig.  249. 


Suppose  the  needle  and  compass  are  pointing  due  north 
and  south  in  the  direction  of  the  line  A  B,  as  shown  in 
Fig.  248,  and  the  line  of  survey  changes  its  direction  45°  to 
the  right,  or  east.  The  magnetic  needle  will  remain  motion- 
less, while  the  sights  and  the  circle  to  which  they  are  fast- 
ened will  move  until  the  sights  point  in  the  direction  C  D, 
Fig.  240,  and,  as  the  north  end  of  the  compass  is  ahead,  the 
needle  will  read  N  45°  E,  which  is  the  true  direction  being 
run.  If,  however,  the  east  and  west  points  of  the  compass 
were  the  actual  magnetic  directions,  i.  e. ,  the  right  hand 
east  and  the  left  hand  west,  the  direction  of  the  line  C  D 


608  SURVEYING. 

would  have  read  N  45°  W,  which  would  be  the  reverse  of 
the  actual  direction. 

1202.  Levels. — On  the  compass  plate  are  two  small 
spirit  levels  F  and  G.  (See  Fig.  247.)  They  consist  of 
glass  tubes,  curved  slightly  upwards  and  nearly  filled 
with  alcohol,  leaving  a  small  bubble  of  air  in  them.  One 
of  these  tubes,  /%  is  in  the  line  of  sight,  the  other,  C, 
is  at  right  angles  to  it.  Their  object  is  to  enable  the 
observer  to  place  the  compass  in  a  perfectly  horizontal 
position.  This  is  done  by  so  moving  the  compass  as 
to  bring  the  air  bubbles  to  the  centers  of  the  tubes.  To 
prove  these  bubbles  to  be  in  adjustment,  proceed  as  fol- 
lows: Having  brought  the  bubbles  to  the  centers  of  the 
tubes,  revolve  the  compass  through  180°  or  one-half  of 
an  entire  revolution.  If  the  bubbles  remain  in  the  cen- 
ters of  the  tubes,  they  are  in  adjustment.  If  they  do 
not  so  remain,  bring  them  half  way  back  to  the  middle 
of  the  tubes  by  means  of  small  screws  attached  to  the 
tubes,  and  the  remainder  of  the  way  by  moving  the  plate 
in  the  ordinary  way,  repeating  the  operation  until  the 
bubbles  remain  in  the  center  of  the  tubes  in  every  position 
of  the  compass. 

1 203.  The  Tripod. — The  compass  is  usually  supported 
by  a  single  standard,  shod  with  steel,  and  called  a  Jacob's 
Staff.  A  more  perfect  support,  called  a  tripod,  consists 
of  three  legs  shod  with  steel  and  connected  at  the  top  so  as 
to  move  freely.  Both  Jacob's  Staff  and  tripod  are  connected 
with  the  compass  by  means  of  a  ball  and  socket  joint,  which 
permits  free  movement  in  all  directions. 

1204.  Defects  of  the  Compass. — The  compass  is 
not  intended  for  work  requiring  great  accuracy.  The  direc- 
tion to  which  the  needle  points  can  not  be  read  with  pre- 
cision, and  the  perfect  freedom  of  movement  of  the  needle 
may  be  prevented  by  local  attraction  or  by  particles  of  dust 
adhering  to  the  pivot.  An  inaccuracy  of  one-quarter  of  a 
degree  in  reading  an  angle,  i.  e.,  the  amount  of  change  in 


SURVEYING.  609 

the  direction  of  two  lines,  will  cause  them  to  separate  from 
each  other  If  feet  in  a  distance  of  400  feet. 

Suppose  the  line  A  B,  Fig.  250,  is  due  east  and  west,  and 
the  line  B  C,  which  is  an  actual  boundary,  has  a  true  direc- 
tion of  N  85°  E,  and  suppose  the  surveyor  reads  the 
directions  ^  6^  as  N  84°  45'  E.  Let  i?  C  =  400  feet,  then, 
the  point  C,  when  mapped,  will  take  the  position  C\  which  is 
If  feet  to  the  left  of  C  where  it  should  be.  Another  defect 
of  the  compass  lies  in  the  fact  that  the  magnetic  needle  does 

C 

A B -—===405*^""^  l^fJ^ 

Fig.  25e. 

not  always  point  in  the  same  direction.  This  direction  some- 
times changes  between  sunrise  and  noon  to  the  amount  of 
one-quarter  of  a  degree.  Frequently  its  direction  is  changed 
by  local  influence.  A  piece  of  iron  on  the  surface  of  the 
ground  or  a  mass  of  iron  ore  beneath  are  frequent  disturbing 
influences. 

1 205.  Taking  Bearings. — The  bearing  of  a  line  is 
the  angle  which  it  makes  with  the  direction  of  the  magnetic 
needle.  By  the  course  of  a  line  we  mean  its  length  and  its 
bearing  taken  together.  To  take  the  bearing  of  a  line,  set 
the  compass  directly  over  a  point  of  it,  at  one  extremity,  if 
possible.  This  may  be  done  by  means  of  a  plumb  bob  sus- 
pended from  the  compass,  or,  if  the  compass  be  mounted  on 
a. Jacob's  Staff,  by  firmly  planting  the  staff  directly  on  the 
line.  Then,  by  means  of  the  air  bubbles,  bring  the  compass 
to  a  perfectly  level  position.  Let  a  flagman  hold  a  rod  care- 
fully plumbed  at  another  point  of  the  line,  preferably  the 
other  extremity  of  it,  if  he  can  be  distinctly  seen.  Direct 
the  sights  upon  this  rod  and  as  near  the  bottom  of  it  as  pos- 
sible. Always  keep  the  same  end  of  the  compass  ahead; 
the  north  end  is  preferable,  as  it  is  readily  distinguished  by 
some  conspicuous  mark,  usually  a  '■'■  fleur  de  lis,"  and  always 
read  the  same  end  of  the  needle,  that  is,  the  north  end 
of  the  needle  if  the  nor  th  point  of  the  compass  is  ahead, 


OlO 


SURVEYING. 


and  vice  versa.  Before  reading  the  angle,  see  that  the  eye 
is  in  the  direct  line  of  the  needle  so  as  to  avoid  error 
which  would  otherwise  result  from  parallax,  or  apparent 
change  of  the  position  of  the  needle,  due  to  looking  at  it 
obliquely. 

The  angle  is  read  and  recorded  by  noting,  first,  whether 
the  N  OT  S  point  of  the  compass  is  nearest  the  end  of  the 
J.        needle    being    read;    second,    the 
y        number   of   degrees   to   which   it 
points,  and  third,  the  letter  E  or 
W  nearest  the  end  of  the  needle 
being  read. 

Let  A  B,  in  Fig.  251,  be  the 
direction  of  the  magnetic  needle, 
B  being  at  the  north  end.  Let 
the  sights  of  the  compass  be 
directed  along  the  line  C  D.  The 
north  point  of  the  compass  will  be 
seen  to  be  nearest  the  north  end 
of  the  needle  which  is  to  be  read.  The  needle  which 
has  remained  stationary  while  the  sights  were  being 
turned  to  C  Z>,  now  points  to  45°  between  the  N  and  E 
points,  and  the  angle  is  read  north  forty-five  degrees  east 
(N45°  E). 


1 206.  Backsights. — A  sure  test  of  the  accuracy  of  a 
bearing  is  to  set  up  the  compass  at  the  other  end  of  the  line, 
i.  e.,  the  end  first  sighted  to,  and  sight  to  a  rod  set  up  at  the 
starting  point.  This  process  is  called  backslKtitliiK.  If 
the  second  bearing  is  the  same  as  the  first,  the  reading  is 
correct.  If  it  is  not  the  same,  it  shows  that  there  is  some 
disturbing  influence  at  either  one  or  the  other  end  of  the 
line.  To  determine  which  of  these  two  bearings  is  the  true 
one,  the  compass  must  be  set  up  at  one  or  more  intermediate 
points,  when  two  or  more  similar  bearings  will  prove  the  true 
one.  When  a  line  can  not  be  prolonged  by  magnetic  bearings, 
on  account  of  local  attraction,  the  true  direction  is  maintained 
by  backsighting. 


SURVEYING,  (311 

1  207.  Declination  of  tlie  Needle. — The  magnetic 
meridian  is  the  direction  of  the  magnetic  needle.  The  true 
meridian  is  a  true  north  and  south  line,  which, 
if  produced,  would  pass  through  the  poles  of  the 
earth.  The  declination  of  the  needle  is  the 
angle  which  the  magnetic  meridian  and  the  true 
meridian  make  with  each  other. 

In  Fig.  252,  let  N  S  he  the  true  meridian  for 
any  given  place,  and  iV  5*  the  magnetic  meridian. 
The  angle  NA  iV*  is  the  declination  of  the  needle 
for  that  place. 

1  208.  The  Polar  Star. — There  is  a  star  in 
the  northern  hemisphere  known  as  the  North  Star 
or  Polaris.  It  is  the  extreme  star  in  the  row  or 
line  of  stars  forming  what  is  commonly  called  the  ^ 
handle  of  the  "Little  Dipper."  This  star  very  ^ 
nearly  coincides  with  the  true  north  point  or  ^"^-  '^^• 
pole,  being  removed  only  1^°  from  it.  It  revolves  about  the 
true  pole,  and  twice  in  each  revolution  it  is  exactly  in  the  true 
^--^^---^  meridian ;  that  is,  in  a  vertical  plane  passing 
through  the  true  pole  P.  See  Fig.  253.  One 
may  know  when  the  North  Star  is  in  the  true 
meridian  from  the  position  of  another  star. 
This  other  star  is  in  the  handle  of  the  "  Big 
Fig.  253.  Dipper, "or  Ursa  Major,  the  one  nearest  the 
bowl  of  the  dipper,  and  is  called  Alioth.  When  the  North 
Star  is  in  the  true  meridian,  Alioth  will  be  found  directly 
below  it.  

TO    DETERMINE    A    TRUE    MERIDIAN. 

1 209.     By  Observations  of  the  North  Star.— The 

time  at  which  the  North  Star  passes  the  meridian  above  the 

pole  for  every  tenth  day  of  the  year  is  given  in  published 

tables,  but  those  occurring  in  the  day  time  are,  of  course, 

of   no-  value  with    ordinary  instruments.       The    following 

dates  are  available  in  almost  every  latitude  of  the  United 

States: 
J' 


O 


012 


SURVEYING. 


TIME  OF  NORTH  STAR  PASSING  THE 
MERIDIAN. 


Months. 

1st  Day. 

11th  Day. 

21st  Day. 

January 

August 

September 

October 

November 

December 

6:30  P.  M. 

4:33  A.  M. 

2:31  A.  M. 
12:34  A.  M. 
10:28  P.  M. 

8:30  P.  M. 

5:51  P.  M. 
3:53  A.  M. 
1 :52  A.  M. 
11:50  P.  M. 
9:48  P.  M. 
7 :50  P.  M. 

5:11  P.  M. 
3:14  A.  M. 
1:12  A.  M. 
11:11  P.  M. 
9:09  P.  M. 
7:11  P.  M. 

Note  from  the  table  the  time  of  passing  the  meridian, 
and,  also,  that  it  is  the  upper  transit,  i.  e.,  above  the  pole. 
Select  a  suitable  spot  for  permanently  establishing  the 
meridian  line,  and  set  up  the  transit  and  sight  to  Polaris, 
following  it  by  moving  the  cross-hairs  with  the  tangent 
screw.  When  it  is  exactly  in  line  with  Alioth,  the  line 
of  sight  will  be  in  the  true  meridian.  Points  should  be  fixed 
immediately,  a  lamp  being  used  to  illuminate  the  cross- 
hairs. 

1210.  Changes   in    Magnetic    Declination. — The 

magnetic  declination  is  not  fixed  for  any  place,  but  con- 
stantly varies,  its  variations,  however,  being  confined  within 
fixed  limits. 

1211.  To  Correct  Magnetic  Bearings. — The  dec- 
lination at  any  place  being  known,  the  magnetic  bearings 
may  readily  be  reduced  to  true  bearings. 

In  the  Northeastern  States,  the  declination  is  west;  in 
the  Western  and  Southern  States,  it  is  east ;  hence,  the  true 
bearing  of  a  line  in  a  Northeastern  State,  whose  magnetic 
bearing  is  N  W  or  S  E,  will  be  the  sum  of  the  magnetic 
bearing  and  the  declination.  If  the  magnetic  bearing  is 
N  E  or  S  W,  the  true  bearing  will  be  the  difference  of 
the  magnetic  bearing  and  the  declination. 


SURVEYING. 


613 


EXAMPLES  FOR  PRACTICE. 


1  212.     Supposing  the  declination  to  be  7°  west,  what'' will  be  the 


true  bearings  of  the  following  lines 
Magnetic  Bearing. 

(1)  N  12°  10'  W  ? 

(2)  N  50°  15'  W  ? 

(3)  S  ir  15'    E  ? 

(4)  S  38°  10'   E  ? 

(5)  N  50°  20'    E  ? 

(6)  S  20°  25'  W  ? 

(7)  N  87°  30'  W  ? 

(8)  N    5°  10'   E  ? 

(9)  S  89°  20'    E  ? 
(10)  S    3°  10'  W  ? 


Ans. 


True  Bearings. 

(1)  N  19°  10'  W. 

(2)  N  57°  15'  W. 

(3)  S  18°  15'   E." 

(4)  S  45°  10'   E. 

(5)  N  43°  20'   E. 

(6)  S  13°  25'  W. 

(7)  S  85°  30'  W. 

(8)  N    1°  50'  W. 

(9)  N  83°  40'    E. 
L  (10)  S    3°  50'   E. 


1213.     By   Equal    Shadows  of  the    Sun. — On  the 

south  side  of  any  level  surface  set  up  a  flag-pole  and  plumb 

it   with    a   plumb    bob.      Its     horizontal 

projection  will   be  a  point  as  S  in  Fig. 

254.     Two  or  three  hours  before  noon 

mark  the  point  yi,  which  is  the  extremity 

of   the    shadow   cast   by   the    flag-pole. 

Then,  describe  an  arc  A  B  with  a  radius 

equal  to  S  A,  the  distance  from  S  to  the 

extremity  of  the  shadow.     After  noon, 

note  the  moment  when  the  shadow  of  the  flag-pole  touches 

another  point  of  the  arc,  as  B.     Bisect  the  arc  A  B  at  N. 

The  line  5  iV  is  a  true  meridian. 


FIELD  WORK. 
1214.  The  Engineer's  Chain. — The  engineer's  chain 
is  one  hundred  feet  in  length,  and  is  composed  of  one  hun- 
dred links  of  steel  wire,  each  one  foot  in  length.  Both  ends 
of  the  chain  are  fitted  with  brass  handles  with  swivel  move- 
ments, and  fitted  with  nuts  for  taking  up  any  excess 
in  length  resulting  from  continual  stretching.  At  each 
interval  of  ten  feet  is  a  brass  tag  with  tally  points  to  indi- 
cate its  distance  from  the  nearest  end  of  the  chain.  Each 
tally  point   counts  ten  feet.     At  the   middle  point  of  the 


614  SURVEYING 

chain,  the  tag  is  of  oval  form  to  prevent  confusion  in  reading 
the  chain. 

1215.  l>anger  of  Error. — There  is  much  greater 
danger  of  error  in  reading  the  chain  than  in  reading  bear- 
ings. The  danger  arises  from  the  fact  that  the  compassman 
is  usually  one  of  experience,  who  knows  the  liability  of  error, 
and  hence  the  necessity  for  care,  while  chainmen  are  often 
inexperienced,  and,  unfortunately,  often  careless. 

1216.  Keeping  Chainmen  in  Line. — When  the 
direction  of  a  line  has  been  given  by  setting  up  a  flag,  it  be- 
comes the  business  of  the  hind  chainman  or  follower  to  keep 
the  measurement  on  a  straight  line.  The  head  chainman 
carries  a  flag  which  he  moves  to  right  or  left,  at  the  di- 
rection of  the  hind  chainman,  until  it  is  in  range  with  the 
flag  towards  which  the  compass  is  sighted,  and  this  process 
is  repeated  at  each  chain  measurement. 

In  railroad  surveying,  the  line  is  divided  into  stations, 
which  are  one  hundred  feet  or  one  chain  apart.  At  each 
station  a  stake  is  driven  and  marked  with  a  number  corre- 
sponding to  the  number  of  chains  which  the  station  is  distant 
from  the  starting  point,  which  is  numbered  0.  When  the 
end  of  a  course  falls  between  regular  stations,  it  is  called  a 
sub-station,  and  the  stake  is  marked  by  the  number  of  the 
immediately  preceding  station  plus  the  number  of  feet  from 
it  to  the  end  of  the  course. 

The  line  A  B,  in  Fig.  255,  is  650  feet  in  length.  The 
starting  point  A  is  numbered  0\  each  chain  or  one  hundred 

0  1 2 3 4 5 6      6+50 

^  Pig.  255.  -^ 

feet  is  marked  by  a  stake  with  numbers  in  regular  notation. 
The  point  B,  which  is  fifty  feet  from  station  6,  is  marked 
6  +  50. 

1217. — The  Compass  in  Railroad  Surveys. — The 

compass  is  of  great  value  in  running  preliminary  railroad 
lines,  where  local  attraction  is  absent  or  very  slight.  The 
numerous  delays  encountered  when  running  by  backsights, 


SURVEYING.  615 

as  in  transit  work,  where  all  obstacles  to  the  line  of  sight 
must  be  cleared,  are  largely  avoided  in  the  use  of  the  com- 
pass. The  directions  of  all  lines  are  referred  to  the  mag- 
netic needle,  and,  in  case  of  an  obstruction,  such  as  a  tree  or 
a  mass  of  rock,  the  compass  can  be  quickly  moved  to  the  op- 
posite side  of  the  obstacle  and  the  line  continued  without 
delay.  In  case  the  line  produced  is  a  foot  or  two  off  the  true 
one,  //  is  a  parallel  to  it,  and  the  error  is  not  to  be  re- 
garded as  affecting  the  accuracy  oi preliminary  information. 
In  the  case  of  transit  work,  an  error  in  the  reading  of  an 
angle  is  a  cunmlative  one,  and  practically  destroys  the  value 
of  the  work.  In  the  early  days  of  railroad  building,  some 
lines  were  surveyed  and  built  with  the  aid  of  the  compass 
alone,  but  in  America  all  location  and  construction  depend 
for  their  precision  upon  the  transit. 

1218.  Organization  of  Party. — A  well-organized 
compass  party  consists  of  a  chief  of  party,  compassman, 
two  chainmen,  one  flagman,  two  or  more  axmen,  if  the 
country  be  thickly  wooded,  and  one  stakeman.  If  possible, 
provide  stakes  of  light,  well-seasoned  wood.  For  preliminary 
lines  where  stakes  do  no  permanent  service,  pine  is  best.  A 
convenient  size  is  two  feet  six  inches  in  length  by  two  inches 
in  width  and  half  an  inch  in  thickness.  A  strong,  active 
stakeman  will  carry  one  hundred  of  these  stakes,  besides 
the  ax  with  which  to  drive  them.  Provide  both  chainmen 
with  marking  crayons.  The  best  crayon  is  of  red  chalk  or 
German  kiel.  They  are  bought  in  a  crude  state,  but  a  little 
work  will  shape  them.  They  make  a  deep  red  mark,  which 
will  stand  exposure  for  years.  Require  chainmen  to  be 
always  provided  with  crayons.  Instances  of  their  forgetful- 
ness  too  often  occur.  Require  axmen  to  keep  axes  sharp. 
A  dull  ax  is  little  better  than  no  ax.  Check  length  of 
chain  with  standard  steel  tape,  lengthening  or  shortening  by 
means  explained  in  Art.  1214.  See  that  the  compass  is  in 
perfect  adjustment.  If  the  line  to  be  surveyed  is  of  consid- 
erable length,  a  team  of  horses  and  driver  with  a  strong 
spring  wagon  should  be  a  part  of  the  outfit. 


616  SURVEYING. 

1219.     Actual   Work. — The  party   is   now   prepared 

to  move.  The  compassman  sets  up  the  compass  at  the 
starting  point,  which  is  marked  0.  The  chief  of  party 
goes  ahead  with  the  flagman,  who  carries  a  rod  called 
a  flag.  This  rod  is  from  eight  to  twelve  feet  in  length, 
and  is  divided  into  alternate  red  and  white  bands,  each 
one  foot  in  length.  The  flagman  sets  this  flag  up  at  the 
direction  of  the  chief  of  party,  the  compassman  sights 
the  instrument  to  it,  and  the  chainmen  commence  meas- 
uring the  distance.  The  head  chainman  marks  the  stakes, 
and  should  always  keep  at  least  ten  stakes  marked  ahead 
so  as  to  avoid  delay  while  measuring,  and  to  insure  con- 
secutive numbering.  Of  these  he  need  carry  but  five, 
leaving  the  remaining  five  with  the  stakeman.  He  must 
also  carry  a  flag  eight  feet  in  length,  and  painted  like 
the  one  carried  by  the  flagman;  this  flag  is  used  for  "rang- 
ing in."  As  soon  as  the  line  is  indicated  by  the  head  flag, 
the  axmen  should  fall  to  work  clearing  whatever  obstacles 
lie  in  the  way  of  rapid  chaining.  By  a  little  attention  on 
their  own  part  and  occasional  direction  from  the  chainmen, 
they  can  keep  well  on  line.  At  each  station,  and  the 
moment  the  hind  chainman  has  put  the  head  chainman  in 

line,  the  former  should 

^^ gQ.t ^  carefully     note    the 

number  of  the  station 

jh;;;^- g^t >,  at  whlch  hc  stands  and 

call  the  number  to  the 
head  chainman  who 
must  answer  by  repeat- 
mg  the  number  next 
in  notation.  Thus,  if  the  hind  chainman  stands  at  Station 
25  he  must  call  "  Station  25,"  and  the  head  chainman  must 
reply  "Station  26."  The  chainmen  must  be  required  to 
hold  the  chain  "  taut "  while  measuring,  and  in  as  nearly 
horizontal  a  position  as  possible.  When  the  line  of  meas- 
urement rises  or  falls  abruptly,  the  chainmen  must  "break 
the  chain,"  as  it  is  called.  The  best  method  of  breaking  the 
chain  is  shown  in  Fig.  256. 


SURVEYING.  617 

Let  A  B  be  a.  sloping  surface  lying  in  tHe  line  of  measure- 
ment. The  point  A  is  at  Station  17.  Stretchout  the  chain 
to  its  full  length  and  in  proper  line.  The  hind  chainman 
will  be  at  Station  17.  The  head  chainman  here  takes  the 
chain  at  the  50-foot  tag  and  raises  it  until  it  is  practically 
level.  The  flag  he  carries  for  ranging  in  will  serve  for  a 
plumb  line  to  mark  the  50-foot  point  on  the  ground.  The 
hind  chainman  then  calls  the  number  of  his  station,  17,  the 
head  chainman  replying  17  +  50.  The  former  then  advances 
to  17  +  50  and  holds  the  middle  tag  at  the  point  marked  by 
the  rod.  The  head  chainman  then  advances  to  the  other 
end  of  the  chain  and  repeats  the  operation,  reaching  Station 
18.  When  the  slope  is  steep,  the  chain  must  be  broken  into 
smaller  sections.  It  is  good  practice  for  the  flagman  to 
carry,  besides  his  flag,  a  number  of  light  stakes  at  least 
eight  feet  in  length  and  some  strips  of  red  flannel  for 
targets.  If  the  view  for  the  compass  is  open,  as  soon  as 
the  compass  is  sighted  and  the  flagman  has  a  signal  to  that 
effect,  he  should  replace  the  flag  by  one  of  the  stakes  with 
a  piece  of  flannel  attached  and  join  the  chief  of  party,  who, 
unless  the  line  is  to  be  produced,  has  gone  ahead  to  select 
another  point  for  the  flag.  As  soon  as  the  compassman  has 
recorded  the  bearing  of  the  line,  he  should  take  the  compass 
and  walk  rapidly  to  the  next  station,  marked  either  by  the 
flag  or  target,  and,  if  in  full  view  of  the  chainmen,  remove 
the  station  mark  and  set  up  the  compass  and  be  prepared  to 
take  the  next  bearing  the  moment  it  is  indicated  by  the 
chief  of  party.  As  soon  as  the  chainmen  reach  the  com- 
pass and  have  "taken  the  plus"  from  the  last  full  station, 
the  hind  chainman  calls  out  the  full  station  and  plus,  which 
the  head  chainman  marks  on  a  fresh  stake  and  which  the 
compassman  records  as  the  length  of  the  course  run.  If  the 
same  line  is  to  be  continued  or  "produced,"  the  compass  is 
set  at  the  same  bearing  as  the  course  just  run  and  the 
chainmen  are  lined  in  by  the  compassman. 

1220.  Example  of  the  Use  of  the  Compass  in 
Railroad    Work. — Suppose  C  A   D  in   Fig.  257  to  be  a 


618 


SURVEYING. 


Bp4H75 


railroad  in  operation,  and  that 
it  has  been  decided  to  run  a 
compass  line  from  the  point  A 
along  the  valley  of  the  stream 
X  Y  to  the  point  B.  The 
bearing  of  the  tangent  A  I) 
can  not  be  determined  by  set- 
ting up  the  compass  at/i,on 
account  of  the  attraction  of 
the  rails.  The  direction  of 
this  tangent,  however,  can  be 
obtained  by  setting  up  the 
cortipass  at  A  and  sighting  to 
the  flag  held  at  D.  The  point 
A^  which  is  the  starting  point 
of  the  line  to  be  run,  is 
marked  0.  Producing  the  line 
A  D  440  feet,  the  point  E  is 
reached,  which  has  been  pre- 
viovisly  indicated  by  the  chief 
of  party  as  a  proper  place  for 
changing  the  direction  of  the 
line.  The  compass  being  set 
up  at  E^  the  bearing  of  the 
line  A  E,  which  is  the  line 
A  D  produced,  is  found  by 
sighting  to  A^  or,  what  is 
preferable,  to  the  point  Z>, 
if  that  point  can  be  seen. 
The  number  of  Station  E^ 
viz.,  4  +  40,  and  the  bearing 


SURVEYING.  619 

of  A  E  are  then  recorded  by  the  compassman.  By  this 
time  the  chief  of  party  has  located  the  point  F^  and  the  flag 
is  in  place  for  sighting.  The  axmen,  if  there  is  work  for 
them  to  do,  are  put  in  line  by  the  head  chainman,  clearing 
only  so  much  as  would  interfere  with  rapid  chaining.  The 
bearing  of  the  line  E  F  being  recorded,  the  compass  is 
moved  quickly  to  /%. replacing  the  target  left  by  the  flagman, 
leveled  up,  and  directed  toward  the  point  6",  which  is  either 
already,  or  soon  will  be,  located.  The  chainmen  reaching 
/%  its  number  11  -|-  20  is  recorded  by  the  compassman,  and 
the  instrument  sighted  to  G  and  the  work  continued  as 
before. 

1221.  Form  for  Keeping  Notes. — A  plain  and  con- 
venient form  for  compass  notes  is  the  following,  which  is  a 
record  of  the  survey  platted  in  Fig,  257:  The  first  column 
contains  the  station  numbers,  the  notation  running  from  the 
bottom  to  the  top  of  the  page.  By  such  an  arrangement, 
the  lengths  of  the  courses  are  found  by  subtracting  the  num- 
ber of  the  station  of  one  compass  point  from  the  number 
of  the  station  of  the  next  succeeding  compass  point. 
Before  commencing  the  plat,  the  subtractions  are  made 
and  the  lengths  of  the  courses  written  in  red  ink  between 
the  station  numbers. 

The  second  column  contains  the  bearings  of  the  lines. 
The  bearing  recorded  opposite  to  a  station  is  the  bearing  of 
the  course  between  the  given  station  and  the  one  next  above. 
Thus,  the  bearing  recorded  opposite  Sta.  0  is  N  75°  00'  W, 
and  is  the  bearing  of  the  line  extending  from  Sta.  0  to  Sta. 
4-|-40  next  above.  The  length  of  the  course  is  the  differ- 
ence between  0  and  4  +  40  equal  to  440  ft.  The  bearing 
recorded  opposite  to  4  +  40  is  N  25°  00'  W.  It  is  the  bear- 
ing of  the  line  extending  from  Sta.  4  +  40  to  Sta.  11  -|-  20 
next  above.  Its  length  is  found  by  subtracting  4  +  40  from 
11  +  20  equal  to  680  ft.,  and  so  on. 

In  the  third  column,  under  the  head  of  remarks,  are 
recorded  notes  of  reference,  topography,  and  any  informa- 
tion which  may  aid  in  platting  or  subsequent  location. 


620 


SURVEYING. 


Station. 

Bearing. 

Remarks. 

47+75 

End  of  line 

35  +  75 

N  25°  40'  E 

27  +  50 

N  14°  10'  E 

20+35 

N    2°  30'  W 

Woodland 

11  +  20 

N 15°  lo:  W 

4  +  40 

N  25°  00'  W 

0 

N  75°  00'  W 

Sta.  0  is  at  P.  C.  of  14°  curve  to 

left  at  Bellford  Sta. O. &P.  R.  R. 

1 222.  Platting. — After  a  survey  has  been  finished,  a 
drawing  is  made  showing  the  courses.  This  drawing  is 
called  a  plat,  and  the  operation  of  making  the  plat  from 
the  field  notes  is  called  platting. 

Since  the  direction  of  every  line  of  a  compass  survey  is 
referred  to  the  same  parallel,  viz.,  the  magnetic  meridian, 
the  readiest  mode  of  platting  such  a  survey  is  by  the  use  of 
the  T  square  and  protractor.  The  lines  drawn  to  a  T  square 
are  parallel,  and  in  platting  take  the  direction  of  the  mag- 
netic needle,  or  meridian. 

The  line  A  B,  described  in  Art.  1 220  and  shown  in  Fig. 
257,  is  platted  as  follows:  The  arrow  shown  in  the  figure 
gives  the  direction  of  the  magnetic  meridian.  A  line  A  L, 
parallel  to  this  meridian,  is  drawn  through  the  starting 
point  A,  and  from  A  as  a.  center  the  line  A  £,  whose  direc- 
tion N  75°  00'  W  is  taken  from  the  field  notes  kept  by  the 
compassman,  is  laid  off  with  a  protractor.  The  directions 
west  are  laid  off  to  the  left  of  the  meridian,  and  those  east 
to  the  right  of  the  meridian.  The  course  A  E,  being  a 
northwest  course,  is  laid  off  to  the  left  of  the  meridian  A  L, 
as  shown  in  the  figure.     The  length  of  the  line  A  E  is  then 


SURVEYING. 


621 


measured  on  this  line  to  any  convenient  scale,  usually  300 
feet  to  the  inch,  and  a  parallel  to  the  magnetic  meridian 
drawn  through  E^  from  which  the  bearing  of  the  line  E  F^ 
viz.,  N  25°  00'  W,  is  laid  off  and  platted.  The  remaining 
courses  are  platted  in  the  same  manner. 


TRANSIT  SURVEYING. 


THE  INSTRUMENT. 
1223.  The  engineer's  transit,  see  Fig.  258,  is  an 
instrument  in  which  the  telescope  stakes  the  place  of  the 
plain  sights  of  the  compass, 
and  in  which  the  angles  are 
read  to  single  minutes  by 
the  vernier.  A  level  C  is 
attached  to  the  underside 
of  the  telescope  and  a  ver- 
tical arc  D  is  attached  to 
the  outside  of  the  left  hand 
standard.  A  vernier  E  for 
reading  vertical  angles  is 
attached  to  the  telescope 
axis  and  adjusted  by  the 
tangent  screw  F.  The 
standards  G  and  G,  which 
support  the  telescope,  are 
fastened  to  the  upper  or 
vernier  plate,  as  is  one  of 
the  levels  7/,  the  other 
being  carried  by  one  of  the 
standards  at  H' .  The  com- 
pass circle  A",  which  is 
divided  like  that  of  the 
ordinary  compass,  is  also  a  fig.  258. 

part  of  the  upper  plate.  The  vernier  plate  covers  the  lower 
or  divided  limb,  of  which  only  two  small  arcs  can  be  seen 
through  the  openings  where   the  verniers  are  placed.     A 


622 


SURVEYING. 


screw  which  clamps  the  vernier  plate  to  the  divided  limb  is 

shown  at  /'.      Slow  motion  is  given   to  the   upper   plate  by 

-Hi  the  tangent  screw  J/,  and  to  the  divided  limb  by 

the  screw  L.     The  transit  is  fastened  to  the  plate 

N  by  a  ball  and  socket  joint,  and  is  leveled   by 

means   of   the    screws   P,    Q,    R,    and   S.     It   is 

fastened  to  the  tripod    7^  in  a  variety  of  ways, 

usually   screwed   to  the  tripod,   the   edge  of  the 

plate  N  being  milled  to  aid  the  operator.     The 

transit   is   brought   to    center   over   a   point    by 

means    of    a    plumb    bob    which    is    suspended 

fastened    to    the    lower   part   of   the 


CQ    !^^ 


o-H 


t^ 


N$ 


by    a    loop 
transit. 

1224.  The  Telescope. — The  telescope  is 

a  combination  of  lenses  placed  in  a  tube  and  so 
arranged  according  to  the  laws  of  optics  that  the 
image  of  any  object  toward  which  the  telescope 
is  directed  shall  be  formed  within  the  tube  by 
the  rays  of  light  coming  from  the  object  and 
^  bent  in  passing  through  the  object  glass.  This 
o  image  is  magnified  by  the  eye-piece,"  which  is 
composed  of  several  lenses.  Telescopes  are  of 
various  kinds,  some  representing  the  object  erect, 
i.  e.,  in  its  natural  position,  others  representing 
the  object  inverted. 

The  telescope  shown  in  Fig.  259  represents  the 
object  in  an  erect  position.  Rays  of  light  from 
the  object  A  fall  upon  the  object  glass  B  where 
they  are  bent,  and,  crossing  each  other,  form  the 
image  at  C  in  an  inverted  position.  Passing  on 
through  the  lens  D,  they  are  refracted  or  bent, 
crossing  each  other  again  before  reaching  the  lens 
at  E.  Passing  through  the  lens  F  they  form  an 
erect  image  at  G,  which  is  in  turn  magnified  by 
the  eye-piece  H. 

1225.  The  Cross-Hairs.— In  order  that 
the  line  of  sight    may   be    precisely    brought    to 


SURVEYING. 


623 


bear  upon  any  point  of  an  object  within  the  field  of  the 
telescope,  two  fine  lines  called  cross-hairs,  or  cross- 
Swires,  are  placed  with  their  intersection  at  the  common 
focus  of  the  object  glass  and  the  eye-piece.  The  inter- 
section of  these  cross-hairs  can  be  seen  through  the 
eye-piece,  and  seems  to  be  in  the  same  position  as  that  of 
the  image  of  the  distant  object. 

The  line  passing  through  the  intersection  of  the  cross- 
hairs and  the  optical  center  of  the  object  glass  is  called  the 
line  of  collimation. 

The  cross-hairs  are  fastened  to  a  thick  brass  ring  placed 
within    the    telescope    and    held    in   position    by    capstan 

headed  screws.  Fig. 
260,  let  into  this  ring. 
They  are  commonly 
placed  at  right  angles  to 
each  other,  the  one  being 
vertical  and  the  other 
horizontal.  The  ring, 
together  with  the  cross- 
hairs, can  be  moved  by 
the  capstan  headed 
screws.  The  cross-hairs 
are  either  of  platinum  wire,  drawn  very  fine,  or  spider  threads. 
Platinum  wire  is  best,  as  it  is  not  affected  by  changes  of 
temperature. 


Fig.  260. 


1226.  Focusing  the  Telescope. — The  movement  of 
the  object  glass  is  effected  by  a  milled  headed  screw  U, 
shown  in  Fig.  258.  This  screw  moves  the  object  glass  out 
or  in,  according  as  the  object  is  nearer  or  further  from  the 
instrument.  The  eye-piece  is  focused  upon  the  cross-hairs 
by  a  similar  screw  V.  The  cross-hairs  are  not  in  proper 
focus  until  they  appear  to  be  a  part  of  the  object  looked  at, 
showing  no  movement,  however  the  position  of  the  eye  may 
be  changed. 

The  telescope  is  supported  upon  an  axis  and  so  placed  that 
both  ends  shall  be  as  nearly  balanced  as  possible.     The  axis 


624  SURVEYING. 

rests  on  upright  legs  called  the  standards.    The  standards 
are  fastened  to  the  upper  plate. 

1 227.  The  Graduated  Circle.— This  circle  is  divided 
into  360  equal  parts  or  degrees,  and  each  degree  is  further 
divided  into  two  or  three  equal  parts.  If  the  degree  is 
divided  into  two  equal  parts,  each  part  equals  30',  and  if 
into  three  equal  parts,  each  part  equals  20'.  The  degrees 
number  from  0  to  360°,  and  in  most  instruments  there  is  an 
inner  graduated  circle,  which  numbers  each  way  from  0  to 
90°,  as  on  the  compass  circle.  Each  tenth  degree  is  num- 
bered; each  fifth  degree  is  indicated  by  a  longer  line  of 
division,  and  each  degree  by  a  line  longer  than  its 
subdivisions. 

1228.  Movements. — When  the  line  of  sight  is  to  be 
brought  to  bear  upon  a  distant  object,  the  observer  turns 
the  telescope  in  the  direction  of  the  object  by  lightly  but 
firmly  grasping  the  upper  plate,  one  hand  on  either  side  of 
the  instrument.  The  eye  is  ranged  along  the  top  of  the 
telescope,  which  is  turned  by  the  hands  until  it  appears  to 
be  in  the  direct  line  of  the  object.  The  eye  is  then  brought 
to  the  eye-piece,  and  the  object  glass  focused  upon  the  ob- 
ject. The  instrument  is  then  clamped,  and,  by  means  of 
either  of  the  tangent  screws,  the  cross-hairs  are  brought 
to  bear  precisely  upon  any  desired  point  of  the  object 
viewed. 

1229.  The  Levels. — Most  of  the  angles  measured  by 
the  transit  are  horizontal  angles,  but  whether  horizontal  or 
vertical,  before  an  angle  can  be  measured,  the  plate  carry- 
ing the  graduated  circle  must  be  brought  to  a  horizontal 
position.  This  is  effected  by  means  of  two  small  levels 
placed  on  the  plate  at  right  angles  to  each  other.  Each 
level  consists  of  a  glass  tube  curved  upwards  at  its  middle 
and  nearly  filled  with  alcohol,  leaving  only  space  for  a 
bubble  of  air.  They  are  so  placed  that  when  the  air  bubbles 
are  exactly  in  the  middle  of  the  tubes,  the  plate  upon  which 
they   rest    will    be   in    a    level    position.       The  leveling  is 


SURVEYING.  625 

performed  by  means  of  four  leveling  screws.  They  have 
milled  heads  and  are  arranged  in  pairs,  the  line  passing 
through  one  pair  being  at  right  angles  to  that  passing 
through  the  other  pair. 

1 230.  To  Level  the  Instrument. — Loosen  the  lower 
clamp  and  bring  one  of  the  bubble  tubes  into  a  parallel  to  a 
plane  passing  through  a  pair  of  opposite  screws.  By  turn- 
ing these  screws,  the  air  bubble  can  be  brought  exactly  to 
the  center  of  the  tube.  As  the  tubes  are  at  right  angles  to 
each  other,  the  putting  of  one  in  position  for  leveling  ad- 
justs the  other  for  leveling  also,  and  having  leveled  one  tube 
with  one  pair  of  screws,  the  other  tube  is  leveled  with  the 
other  pair. 

1231.  The  Vernier.  — A  vernier  is  a  contrivance  for 
measuring  smaller  portions  of  space  than  those  into  which 


9\0 


7\0 


Fig.  261. 

a  line  is  actually  divided.  The  divided  circle  of  the  transit 
is  graduated  to  half  degrees,  or  30'.  The  graduations  on  the 
verniers  run  in  both  directions  from  its  zero  mark,  making 
two  distinct  verniers,  one  for  reading  angles  turned  to  the 
right,  and  the  other  for  reading  those  turned  to  the  left. 
Each  vernier  is  divided  into  30  equal  spaces,  which  are  to- 
gether equivalent  to  29  spaces  on  the  divided  circle ;  hence, 
each  space  on  the  vernier  is  equal  to  29',  and  the  vernier  is 
described  as  reading  to  minutes.  In  reading  the  vernier,  the 
observer  should  first  note  in  which  direction  the  graduations 
of  the  divided  circle  run.  In  Fig.  301  the  graduations  in- 
crease from  left  to  right  and  extend  from  57°  to  91°.  Next 
he  should  note  the  point  where  the  zero  mark  of  the  vernier 
comes  on  the  divided  circle.  In  Fig.  201,  the  zero  mark 
comes  between  7-4°  and  74^°.     Now,  as  the  circle  graduations 


626 


SURVEYING. 


read  from  left  to  right,  we  read  the  right-hand  vernier 
and  find  that  the  23d  graduation  on  the  vernier  coincides 
with  a  graduation  on  the  divided  circle,  and  the  vernier 
reads  23',  which  we  add  to  74°,  making  a  reading  of  74°  23', 
an  angle  to  the  left.  In  Fig.  262  the  graduations  on  the 
circle  increase  from  right  to  left,  and  we  accordingly  read 
the  left-hand  vernier.  The  zero  mark  of  the  vernier  comes 
between  67^  and  68°.     Reading  the  vernier,  we  find  that  the 


uiu 


7\0  ^*" 


Fig.  262. 


13th  graduation  on  the  vernier  coincides  with  a  graduation 
on  the  circle,  and  the  vernier  reads  13'.  Accordingly,  we 
add  to  67^°,  the  vernier  reading  of  13',  making  a  total  read- 
ing of  67°  43',  an  angle  to  the  right. 


ADJUSTING    THE   TRANSIT. 

1232.  The  constant  use  of  an  instrument  tends  to  dis- 
arrange some  of  its  parts,  which  detracts  from  the  accuracy 
of  its  work,  without  in  any  way  injuring  the  instrument 
itself. 

The  correction  of  this  disarrangement  of  parts  is  called 
making  the  adjustments. 

The  transit,  when  leveled  up,  will,  if  in  adjustment,  fulfil 
the  following  conditions,  viz. : 

1.  It  will  maintain  a  perfectly  horizontal  position 
during  an  entire  revolution. 

2.  The  line  of  sight,  when  directed  in  opposite  direc- 
tions, will  be  in  the  same  straight  line  ;  and 

3.  The  line  of  sight  will  revolve  in  a  vertical  plane 
perpendicular  to  the  horizontal  plane  of  revolution. 


SURVEYING.  627 

The  adjustments  should  be  made  in  the  order  of  these 
three  conditions.  The  best  time  of  the  day  for  making  the 
adjustments,  especially  in  the  summer  season,  is  the  early 
morning,  before  the  air  has  become  heated  and  the  sun 
dazzling. 

1233.  First  Adjustment. — Secure,  if  possible,  an 
open  space  where  a  clear  sight  may  be  had  for  at  least  400 
feet  in  both  directions  from  the  transit.  Plant  the  feet  of 
the  tripod  firmly  in  the  ground,  and  then  bring  the  plate  to 
a  horizontal  position  with  the  leveling  screws.  Next  turn 
the  vernier  plate  half  way  around,  i.  e.,  revolve  it  through 
an  angle  of  180°.  If  the  bubbles  are  in  adjustment  they 
will  remain  stationary  in  the  centers  of  the  tubes.  If  they 
do  not  remain  so,  but  run  to  either  end,  bring  them  half  way 
back  to  the  middle  of  the  tubes  by  means  of  the  capstan 
headed  screws,  attached  to  the  tubes,  and  the  rest  of  the  way 
back  by  the  leveling  screws.  Then,  revolve  them  again 
through  180°.  Sometimes  this  adjustment  is  made  by  one 
trial,  but  it  is  usually  necessary  to  repeat  the  operation. 

1  234.  Second  Adjustment. — To  cause  the  line  of  col- 
limation  to  revolve  in  a  plane  : 


Fig.  263. 

Measure  from  A,  where  the  instrument  is  stationed  (see 
*Fig.  203),  400  feet  to  the  point  B,  where  a  pin  (or  tack,  if 
it  can  be  seen)   is  fixed. 

Carefully  direct  the  line  of  sight  to  this  point,  and  re- 
verse the  telescope,  i.  e.,  ttirn  it  on  its  axis  until  it  points 
in  the  opposite  direction.  If  the  line  of  collimation  is  "in 
adjustment,"  a  pin  set  400  feet  from  A,  on  the  opposite  side 
of  the  instrument  from  j5,  will  be  at  /^and  in  the  same  line 
2i%  A  B\  \i  '\X.  is  not  in  adjustment,  the  pin  will  be  on  one 
side  of  /%  as  at  D.  Turn  the  vernier  plate  half  way  around, 
that  is,  through  180°,  and  direct  the  line  of  sight  again  to  B. 


628  SURVEYING. 

Reverse  the  telescope,  and  the  pin  will  be  at  C.  Carefully 
measure  the  distance  C  D,  and  at  E,  one-fourth  of  the  dis- 
tance from  C  to  D,  set  the  pin.  Move  the  cross-hairs  by 
means  of  the  capstan  headed  screws  until  the  vertical  hair 
shall  exactly  cover  the  pin  at  E,  being  careful  to  move  them 
in  the  opposite  direction  from  that  in  which  it  would  appear 
they  should  move.  This  movement  having  been  made  and 
the  telescope  reversed,  the  line  of  sight  will  not  be  at  the 
point  y>,  but  at  G,  a  distance  from  B  equal  to  C  E.  Again 
sight  to  B^  and,  reversing,  the  pin  will  be  at  /%  in  the  same 
line  as  A  B.  It  may  be  necessary  to  repeat  the  operation 
to  secure  an  exact  adjustment.  If  so,  take  a  new  set  of 
points,  a  few  inches  removed  from  those  first  used,  to  avoid 
confusion. 

1235.     Third   Adjustment. — To   cause    the    line    of 
collimation  to  revolve  in  a  vertical  plane: 

Suspend  a  plumb  bob  at  as  high  an  elevation  as  can  be 
A  readily  found;  direct  the  line  of  sight  to  the 
upper  end  of  this  line  and  then,  revolving  the 
telescope  slowly  downwards,  see  if  the  intersec- 
tion of  the  cross-hairs  closely  follows  this  line 
throughout  its  length.  If  it  does  follow  it,  the 
line  of  collimation  revolves  in  a  vertical  plane. 
If  it  does  not,  the  adjustment  may  be  made  as 
follows:  Take  a  point  A^  in  Fig.  204,  on  a  church 
spire  or  some  other  high  object,  and  sight  care- 
fully to  it.  Depress  the  telescope  until  a  pin  can 
be  set  in  the  ground  at  its  base,  as  at  B.  Loosen 
the  clamp  and  turn  the  plate  through  180°  with- 
out touching  the  telescope.  Clamp  the  instru- 
B^—i^-^C  ment  and  sight  again  to  the  high  point  A.  Again 
Fig.  264.  depress  the  telescope  and  set  another  pin,  which 
it  will  be  found  is  at  some  distance  from  B^  as  at  C.  The 
vertical  plane  is  the  line  A  D,  and  it  will  be  seen  that  the 
error  is  doubled.  The  adjustment  is  made  by  raising  or 
lowering  one  end  of  the  telescope  axis  by  means  of  a  small 
screw  placed  in  the  standard  for  that  purpose. 


SURVEYING.  629 

DIRECTIONS  FOR   USING   THE  TRANSIT. 

1 236.  Care  of  the  Transit. — The  transit,  though  it 
will  bear  a  lifetime  of  legitimate  service,  will  not  stand 
neglect  or  banging.  The  bearings  are  delicate  and  easily 
marred  by  particles  of  dust  or  sudden  blows.  Moisture 
clouds  the  lenses,  and,  when  combined  with  dust,  is  doubly 
injurious.  Little  advantage  is  gained  from  working  in  the 
rain,  and,  unless  the  stress  of  work  requires  it,  both  instru- 
ment and  men  are  better  off  under  cover.  If  the  instru- 
ments should  encounter  a  wetting,  carefully  wipe  the  object 
glass,  eye-piece,  and  verniers  with  a  piece  of  chamois  skin, 
as  moisture  soon  clouds  them  so  as  to  prevent  further  work. 
As  soon  as  the  party  returns  to  office  or  camp,  complete  the 
drying  process  by  thoroughly  rubbing  with  a  piece  of 
chamois  skin,  which  every  engineering  party  should  carry. 
When  a  party  rides  to  and  from  work,  the  instruments 
should  be  carried  in  their  cases,  and  they  should  always  be 
kept  in  their  cases  when  in  the  office.  The  common  cus- 
tom of  leaving  an  instrument  on  its  tripod  and  standing  on 
a  board  floor  can  not  be  too  severely  condemned. 

1237.  Setting  Up  the  Instrument. — As  much  of 
the  work  of  an  engineering  party  is  suspended  while  the 
instrument  is  being  set  up,  it  is  highly  important  to  acquire 
facility  in  setting  it  up.  The  following  suggestions  will  be 
of  use,  although  practice  alone  will  make  one  expert. 

In  setting  up  a  transit,  three  preliminary  conditions 
should  be  met  as  nearly  as  possible,  viz.  : 

1.  The  tripod  feet  should  be  firmly  planted. 

2.  The  plate  on  which  the  leveling  screws  rest  should  be 
level;  and 

3.  The  plumb  bob  should  be  directly  over  the  given 
point. 

The  third  condition  must  be  met  to  a  nicety,  and  this  is 
rendered  comparatively  easy  by  means  of  a  "  shifting  head  " 
with  which  most  modern  transits  are  provided.  When  these 
three  conditions  are  approximately  met,  the  completion  of 
the  operation  is  quickly  performed  with  the  leveling  screws. 


630  SURVEYING. 

1 238.  How  to  Prolong  a  Straight  Line.— Let  A  B, 
in  Fig.  265,  be  a  straight  line,  and  it  is  required  to  prolong 
or  produce  it  400  feet  to  C. 


400' 

Fig.  265. 

The  line  can  be  prolonged  in  two  ways — by  means  of 
foresiglit  and  backsight. 

1.  By  foresight,  set  up  the  transit  at  A  and  sight  to  B ;  let 
the  chainman  measure  400  feet  from  B  in  the  direction  in 
which  the  line  is  to  be  prolonged.  Then,  by  means  of  signals, 
move  the  flag  to  right  or  left  until  the  vertical  cross-hair 
shall  exactly  divide  the  flag  held  at  C.  Then,  the  line  B  C 
will  be  the  prolongation  of  the  line  A  B. 

2.  By  backsight,  set  the  transit  at  B  and  sight  to  A. 
Reverse  the  telescope,  and,  having  measured  400  feet  from 
B  in  the  opposite  direction  from  A,  set  the  flag  at  C,  then 
the  line  B  C  will  be  the  line  A  B  produced. 

1 239.  Double  Centers. — In  prolonging  lines,  a  device 
known  as  double  centering  is  sometimes  used.  It  is  un- 
necessary when  using  an  instrument  that  is  in  proper 
adjustment,  but  it  is  a  good  check,  and  a  knowledge  of  the 
method  is  valuable. 

Let  A  B,  in  Fig.  2G6,  be  a  given  line  which  it  is  re- 
quired to  produce  1,000  feet,  ^et  up  the  transit  at  B; 
^  g  500\ P  SOO*  O 

Fig.  266. 

backsight  to  A,  and  reverse  the  instrument.  Set  a  point  C 
600  feet  from  B.  Unclamp  the  upper  plate  and  revolve  the 
telescope  through  180°,  backsighting  again  to  A.  Reverse 
the  telescope.  If  the  line  of  sight  does  not  come  at  C,  then 
the  point  C  is  not  in  line  with  the  points  A  and  B,  and  the 
line  of  sight  will  be  at  some  point,  as/),  on  the  opposite  side 
of  the  true  line.  Measure  the  space  C  D  and  mark  its  mid- 
dle point  E.     The  point  E  will  be  in  the  prolongation  of  the 


SURVEYING.  631 

line  A  B.  Move  the  transit  to  E,  and,  backsighting  to  B^ 
determine  the  point  H  by  the  same  means  used  in  fixing 
the  point  E. 

1240.  Horizontal  Angles  and  Their  Measure- 
ment.— A  horizontal  angle  is  one  the  boundary  lines  of 
which  lie  in  the  same  horizontal  plane.  Let  A,  B,  and  C, 
in    Fig.    267,    be    three 

points,  and  let  it  be  re-  .3,°30^- 

quired  to  find  the  hori-  A  ^ 

zontal  angle  formed  by  / 

the  lines  A   B  and  A  C    » i 

joining     these     points. 

Set  up  the  instruments  ^'^-  ^'^• 

precisely  over  the  angular  point  A,  and  carefully  level  it. 
Set  the  vernier  at  zero,  and  place  the  flag  at  B  and  at  C 
Sight  the  flag  at  B  and  set  the  lower  clamp.  Then,  by 
means  of  the  lower  tangent  screw  cause  the  vertical  cross- 
hair to  exactly  bisect  the  flag  at  B.  Loosen  the  upper 
clamp.  With  a  hand  on  either  standard,  turn  the  telescope 
in  the  same  direction  as  that  of  the  hands  of  a  watch  until 
the  flag  at  C  is  covered  or  nearly  covered  by  the  vertical 
cross-hair.  Clamp  the  upper  plate  and  with  the  upper  tan- 
gent screw  bring  the  line  of  sight  exactly  on  the  flag  at  C. 
The  arc  of  the  graduated  circle  traversed  by  the  zero  point 
of  the  vernier  will  be  the  measure  of  the  angle  B  A  C,  equal 
to  143°  30'.  The  points  A,  B,  and  C  are  not  necessarily  in 
the  same  horizontal  plane,  but  the  level  plate  of  the  instru- 
ment projects  them  into  the  horizontal  plane  in  which  it 
revolves. 

1 24 1 .  A  Deflected  Line. — A  deflected  line,  or  "  angle 
line,"  is  a  consecutive  series  of  lines  and  angles.  The  direc- 
tion of  each  line  is  referred  to  the  line  immediately  pre- 
ceding it,  which  preceding  line  is,  in  imagination,  produced, 
and  the  angle  measured  between  it  and  the  next  line  actually 
run.  The  angles  are  recorded  R'  or  IJ,  according  as  they 
are  turned  to  the  right  or  left  of  the  prolongation  of  the 
immediately  preceding  line.     An  example  of  a  deflected  line 


632 


SURVEYING. 


«v 


N 


^^^. 


is  shown  in  Fig.  2G8.  Here  the  start- 
ing point,  A,  of  the  line  is  a  point  in 
the  head-block  of  the  switch  at  Benton 
Station,  O.  &  P.  R.  R.  The  point  A 
is,  of  course,  in  the  center  line  of  the 
track. 

Set  up  the  transit  at  A  with  the 
vernier  at  zero.  Sight  to  a  flag  held 
at  F  on  the  center  line  of  the  track, 
O.  &  P.  R.  R.  Loosen  the  vernier 
clamp,  and  turn  the  telescope  sight 
to  a  flag  held  at  B,  the  next  point  on 
the  angle  line ;  clamp  the  vernier,  and, 
by  means  of  the  tangent  screw,  ac- 
curately sight  to  the  flag  held  at  B; 
the  angle  reads  32°  30',  and  is  record- 
ed R^  32°  30',  with  a  sketch  showing 
the  connection  in  which  the  term 
head-block  is  designated  by  the  abbre- 
viation//^.  ^.  The  bearing  of  the  line 
A  B  can  not  be  taken  at  A  on  account 
of  the  attraction  of  the  rails.  The 
instrument  is  now  moved  to  B,  the 
vernier  set  at  zero  and  backsighted 
to  A ;  the  bearing  oi  A  B,^  75°  00' 
E,  is  taken,  and  the  number  of  sta- 
tion -5,  2  +  90,  together  with  the  bear- 
ing of  A  B,  recorded.  The  telescope 
is  then  reversed,  pointing  in  the  di- 
rection B  B'.  The  point  C  being  de- 
termined, the  upper  clamp  is  loosened 
and  the  telescope  turned  to  the  right 
and  sighted  to  C.  The  reading  of  the 
angle  is  found  to  be  14°  30',  and  re- 
corded R*  14°  30'.  It  measures  the 
angle  B'  B  C.  The  bearing  of  the 
line  B  C,  N  89°  20'  E,  is  then  re- 
corded.    The  instrument  is  next  set 


SURVEYING. 


633 


up  at  C,  the  vernier  set  at  zero,  backsighted  to  B,  and  then 
reversed ;  the  deflection  to  D,  R'  10°  00',  is  then  read  and 
recorded,  together  with  the  number  of  the  station  at  C, 
6  +  85.     This  deflection   measures   the  angle  C  C  D,  and 


Station. 

Defleetio-i   Mag. Bearing. 

Ded.  Bearing. 

Remarks. 

13+63 

End  of  Line. 

10+31 

L'30°00' 

y.  69°25'E. 

y.  69°30'E. 

:^^^ 

6+85 

B'10°00' 

8.  80°30'E. 

S.80°30'E. 

^^n. 

2+90 

R^14°30' 

N.  89°20'E. 

N.89°30'E. 

H  nnf  Stuilr.K 

0 

N.75°00'E. 

8taM\ 

at  Benton  Sta. 

gives  the  direction  of  the  line  C  D.     A  good  form  of  notes 
for  such  a  survey  is  that  given  above. 

1  242.  Checking  Angles  by  the  Needle. — In  spite  of 
the  greatest  care,  errors  in  the  reading  and  recording  of 
angles  will  occur.  The  best  check  to  such  errors  is  the 
magnetic  needle.  And  though  it  is  not  an  exact  check, 
owing  to  the  lack  of  precision  in  reading  the  needle  and  to 
local  attraction,  yet  it  is  the  only  reliable  one,  and  in 
universal  use. 

In  Fig.  269,  we  have  an  example  of  the  use  of  the  needle 


Fig.  269. 


G34 


SURVEYING. 


in  checking  angles.  The  bearing  of  the  line  A  B,  which 
corresponds  to  y^  i^  in  Fig.  208,  is  N  75"  00'  E,  and  is 
assumed  to  be  correct.  The  bearing  of  the  line  B  C,  as  read 
from  the  needle,  is  N.  80°  20'  E.  Its  deduced  or  calcu- 
lated bearing  is  obtained  as  follows:  To  the  bearing  of 
the  line  A  B,  N  75°  00'  E,  we  add  the  R'  deflection  14°  30'; 
the  sum  is  89°  30',  which  is  recorded  in  the  column  headed 
Ded.  Bearing.  (See  Art.  1241.)  The  deduced  bearing, 
it  will  be  seen,  is  ten  minutes  greater  than  the  magnetic 
bearing  as  read  from  the  needle  and  recorded  in  the  column 
headed  Mag.  Bearing.  Had  the  deflection  angle  been  re- 
corded L*  instead  of  R',  the  deduced  bearing  would  have 
been  the  difference  between  75°  00'  and  14°  30',  which  is 
60°  30',  and  would  be  recorded  N  60°  30'  E.  The  magnetic 
bearing  being  N  89°  20'  E  would  have  at  once  revealed  the 
error.  The  confusion  of  the  directions  R'  and  L'  is  the  com- 
monest source  of  error  in  recording  deflections,  though 
sometimes  a  mistake  of  ten  degrees  is  made  in  reading  the 
vernier.  It  is  a  wise  precaution  to  read  both  angle  and 
bearing  after  they  are  recorded  and  compare  them  with  the 
recorded  readings. 


81^18^7 
B 


TRIANGULATION. 
1243.     Simple  Triangrulatlon. — Triangulation   is 

an    application  of  the    principles  of   trigonometry   to   the 

measurement  of  in- 
accessible lines  and 
angles.    A  common 
— -^  occasion  for  the  use 

'  of   trigonometry   is 

illustrated  in  Fig. 
270,  where  the  line 
of  survey  crosses  a 
stream  too  wide  and 
deep  for  actual 
measurement.  Set 
two  points  A  and 
B  on   line,  one   on 


Fig.  270. 


SURVEYING.  635 

each  side  of  the  stream.  Estimate  roughly  the  distance 
A  B.  Suppose  the  estimate  is  425  feet.  Set  another  point 
C,  making  the  distance  A  C  equal  to  the  estimated  dis- 
tance A  B  =  425  feet.  Set  the  transit  at  A  and  measure 
the  angle  B  A  C  =  say  79°  00'.  Next  set  up  at  the  point 
C  and  measure  the  angle  A  C  B  -=  say  5G°  20'.  The 
angle  A  B  C  is  then  determined  by  subtracting  the  sum 
of  the  angles  A  and  C  from  180° ;  thus,  79°  00'  +  50°  20'  = 
135°  20'.  180°  00'- 135°  20'=  44°  40'=  the  angle  ABC. 
We  now  have  a  side  and  three  angles  of  a  triangle  given, 
to  find  the  other  two  sides  A  B  and  C  B.  These  sides 
may  be  easily  found  by  the  methods  given  for  the  solution 
of  triangles  (see  Arts.  '759,  etc.)  by  drawing  a  line  from 
the  vertex  of  one  of  the  angles  A  or  C  so  as  to  divide 
the  triangle  ABC  into  two  right-angled  triangles.  A 
simpler  and  easier  method,  however,  is  the  following:  In 
higher  works  on  trigonometry,  it  has  been  demonstrated 
that,  in  any  triangle,  the  sines  of  the  angles  are  proportional  to 
the  lengths  of  the  sides  opposite  to  them.  In  other  words, 
sin  A  :  sin  B ::  B  C  :  A  C;  or,  sin  A  :  sin  C::B  C  :  A  B,  and 
sin  B  :  sin  C::A  C  :  A  B. 

Hence,  we  have  sin  44°  40'  :  sin  56°  20' ::  425  :  side  A  B. 
Sin  56°  20' =  .83228;  . 
.83228  X  425  =  353.719; 
sin  44°  40'  =  .70298; 
353.719  -^. 70298  =  503.17  ft.  =  side  A  B. 

Adding  this  distance  to  76  +  15,  the  station  of  the  point 
A,  we  have  81  +  18.17,  the  station  at  B. 

Another  and  frequent  occasion  for  the  use  of  trigonome- 
try is  the  following:  Two  tangents,  A  B  and  C  D,  Fig.  271, 
which  are  to  be  united  by  a  curve,  meet  at  some  inaccessi- 
ible  point  E.  Tangents  (which  will  be  more  fully  described 
later  on)  are  the  straight  portions  of  a  line  of  railroad.  The 
angle  C  E  F,  which  the  tangents  make  with  each  other,  and 
the  distances  B  E  and  C  E  are  required.  Two  points  A  and 
B  of  the  tangent  A  B,  and  two  points  C  and  D  of  the  tan- 
gent C  D,  being  carefully  located,  set  the  transit  at  />',  and. 


636 


SURVEYING. 


backsighting  to  A,  measure  the  angle  E  B  C  =  21°  A5' ;  set 
up  at  C,  and  backsighting  to  D,  measure  the  angle 
£  C  B=21°  25'.     Measure  the  side  B  C=  304.2  ft. 

F 


Angle  C'^jp  being  exterior  to  the  triangle  E  B  C  is  equal 
(see  Art.  1 1 94)  to  the  sum  of  E  B  C  and  E  C  B  =21°  45'+ 
21°  25'  =  43°  10'.  The  angle  B  £  C=  180°  -C  E  E  = 
136°  50'. 

From  the  principle  stated  we  have  sin  136°  50'  :  sin 
21°  45'  ::  304.2  ft.   :  side  C  E. 

Sin  21°  45'  =  .37056; 

.37056  X  304.2  =  112.724352; 

sin  136°  50'  =  .68412; 

side  CE=s,  112.724352  -r-  .68412  =  164.77  ft. 


4^ 


/50' 


ly 


•60 


~^ 


J 


.1^^ 


y 


FlO.  272. 

Again,  we  find  B  E  by  the  following  proportion: 

Sin  136°  50'  :  sin  21°  25'  ::  304.2  :  side  B  E\ 

sin  21°  25' =  .36515; 

.36515  X  304.2  =  111.07863; 

sin  136°  50'  =  .68412; 

side^-£'=  111.07863-^.6841^=162.36  ft. 


SURVEYING 


637 


A  building  //,  Fig.  272,  lies  directly  in  the  path  of  the 
line  A  B  which  must  be  produced  beyond  H.  Set  a  plug  at 
B  and  then  turn  an  angle  D  B  C  =  00°.  Set  a  plug  at  C  in 
the  line  B  C,  at  a  suitable  distance  from  B,  say  150  feet. 
Set  up  at  C,  and  turn  an  angle  B  C  D  =  60°,  and  set  a  plug 
at  D,  150  ft.  from  C.  The  point  D  will  be  in  the  prolong- 
ation of  A  B.  Then,  set  up  at  D  and  backsighting  to  C, 
turn  the  angle  C  D  D'  =  120°.  I)  D'  will  be  the  line  re- 
quired, and  the  distance  B  D  will  be  150  feet,  since  BCD 
is  an  equilateral  triangle. 

A  B  and  C  D,  Fig.  273,  are  tangents  intersecting  at  some 


inaccessible  point  H.     The  line  A  B  crosses  a  dock  O  P,  too 


038  SURVEYING. 

wide  for  direct  measurement,  and  the  wharf  L  M.  /^  is  a 
point  on  the  Hne  A  B  at  the  wharf  crossing.  It  is  required 
to  find  the  distance  B  //and  the  angle  F  //  G.  At  />,  an 
angle  of  103°  30'  is  turned  to  the  left  and  the  point  E  set 
217'  from  B  =  to  the  estimated  distance  B  F.  Setting  up 
at  E,  the  angle  B  F  F  is  found  to  be  39°  00'.  Whence,  we 
find  the  angle  B  F  F  =  1S0°  -  (103°  30' +  39°)  =37°  30'. 
From  the  above  principle  we  have  sin  37°  30'  :  sin  39°  00'  :: 
217  ft.    :  side  B  F. 

Sin  39°  00'  =  .02932; 

.02932  X  217  =  130.50244; 

sin  37°  30' =  .00870; 

side  B  F=  130.50244  ^  .00870  =  224.33  ft. 

Whence,  we  find  the  station  of  Fto  be  20  +  17  -f-  224.33  = 
22  +  41.33.  Setup  at  F  and  turn  an  angle /TT^  6^  =  71°  00', 
and  set  up  at  a  point  G  where  the  line  C  D  prolonged  inter- 
sects/^ G.  Measure  the  angle  F  G  H  —  57°  50',  and  the  side 
F  G  =  180. 3'.  The  angle  F  H  G  =180°  -  (71°  +  57°  50')  = 
51°  10'.  From  the  same  principle  as  before  we  have  sin 
51°  10'  :  sin  57°  50'  ::  180.3'  :  side  F  H. 

Sin  57°  50'  =  .84050; 

.  84050  X  180. 3  =  152. 02395 ; 

sin  51°  10' =  .77897; 

side  FH=  152.02395  -^  .77897  =  195.93  ft. ; 

whence,  we  find  the  station  of  H  to  be  24+  37.20. 

1244.  Vertical    Angles. — A  vertical   angle  is  an 

ry p  angle  formed  by  two  intersecting 

lines  lying  in  the  same  vertical 

plane,  one  of  which  is  horizontal. 

If  the  lines  A  B  and  A  C,  Fig. 

jM^  '-^L  274,  lying  in  the  vertical  plane 

FIG. 274.  D  FFG,  meet  at  the  point  A, 

and  the  line  A  B  is  horizontal,  the  angle  C  A  B  is  a  vertical 

angh\  and  is  measured  by  the  arc  B  C. 

1245.  Intersection   of  Tangents. — Let   A   B  and 

C  D,  Fig.  275,  be  tangents  whose  point  of  intersection  is  to 


SURVEYING.  639 

be  determined  and  the  angle  which  they  make  with  each  other 
to  be  measured.  First  set  up  a  flag  or  stake  at  B  and  another 
at  ^,  or  some  other  point  in  the  line  A  B.  Set  up  the  tran- 
sit at  C,  backsighting  to  D.  Reverse  the  instrument. 
Have  a  flagman  hold  a  rod  in  the  line  C  D,  at  the  same  time 
putting  himself  in  range  with  the  stakes  at  A  and  B.  With 
a  little  practice  he  can  nearly  determine  the  intersection  / 
of  the  two  lines.  Then  drive  two  stakes  K  and  L  firmly 
in  the  line  C  D,  one  on  each  side  of  the  point  /.  Their  dis- 
tance from  the  point  /  to  be  determined  by  the  obtuseness 

'^y^C  Angle  of  Intersection, 


\. 


-/ 


C 


Fig.  275. 

of  the  angle  AID.  Carefully  center  these  stakes,  driving 
a  tack  half  its  length  in  each  center.  Stretch  a  cord  between 
these  tacks.  Next  set  up  the  instrument  at  B^  backsighting 
to  A.  Reversing  the  telescope,  set  a  flag  at  /,  which  will 
be  the  intersection  of  the  line  A  B  prolonged  with  L  D. 
Drive  a  stake  flush  with  the  ground  at  /and  drive  a  tack  in 
this  stake  where  the  prolongation  of  A  B  crosses  the  cord 
connecting  the  stakes  at  A' and  L.  The  point  /is  the  inter- 
section of  the  tangents  A  B  and  C  D.  The  external  angle 
C  I M,  formed  by  the  intersecting  tangents,  is  called  the 
angle  of  intersection. 

CURVES. 
1 246.  A  line  of  railroad  consists  of  a  series  of  straight 
lines  and  curves.  In  general,  the  straight  lines,  or,  more 
properly,  the  tangents,  are  first  located  and  then  they  are 
united  by  curves  best  fitting  the  ground  lying  between  the 
tangents.  There  are  certain  limits  of  curvature  prescribed 
for  all  roads,  which  must  not  be  exceeded.     These  limits 


640 


SURVEYING. 


will  depend  upon  conditions  to  be  explained  later.  Rail- 
road curves  are  circular  and  are  divided  into  simple,  covi- 
pojind,  and  reverse  curves. 

A  simple  curve  has  but  one  radius,  as  y^  ^5  in  Fig.  276, 
whose  radius  is  A  C. 

A  compound  curve,  shown  in  Fig.  277,  is  a  continuous 


H 

Fig.  277. 

curve  of  two  or  more  arcs  of  different  radii,  as  C  D  E  F, 
which  is  composed  of  the  arcs  C  D,  D  E,  and  E  F,  whose 
respective  radii  are  G  C,  H  D,  and  K  E. 

A  reverse  curve,  Fig.  278,  is  a  continuous  curve  com- 
posed of  two  arcs  L  M  and  M  N  oi  the  same  or  of  different 

radii  described  in  the  opposite 
directions,  and  having  a  com- 

^^ ~  /  x  mon  point  J/,  called  the  point 

of  reversal.     Reverse  curves, 

though  common  in  the  early 

days  of  railroad  building  in  the 

0  United   States,  are    now  con- 

P'^-  *"*•  demned  for  roads  of  standard 

gauge,  and  only  admitted  for  narrow-gauge  roads,   when 

cheapness  of  construction  is  the  first  requirement. 

1247.  Geometry  of  the  Circle. — Before  attempting 
to  lay  out  curves,  a  knowledge  of  geometry  relating  to  the 
circle  must  be  mastered.  The  following  propositions  are  of 
special  importance: 

1.  A  tangent  to  a  circle  is  perpendicular  to  the  radius 
drawn  through  its  tangent  point.  Thus,  A  E,  Fig.  279,  is 
perpendicular  to  B  O,  and  C  E  is  perpendicular  to  C  O. 


SURVEYING. 


641 


2.  Two  tangents  drawn  to  a  circle  from  any  point  are 
equal,  and  if  a  chord  be  drawn  joining  these  points,  the 
angles  between  the  chord  and  the  tangents  are  equal.  Thus, 
B  E  and  C  E  are  equal,  and  the  angles  E  B  C  and  E  C  B 
are  equal. 

3.  An  acute  angle  between  a  tangent  and  a  chord  is 
equal  to  half  the  central  angle  subtended  by  the  same  chord; 
thus,  the  angle  EBC=ECB  =  one-half  B  O  C, 


4.  An  acute  angle  subtended  by  a  chord,  and  having  its 
vertex  in  the  circumference  of  a  circle,  is  equal  to  half  the 
central  angle  subtended  by  the  same  chord.  Thus,  the 
angle  E  B  6",  whose  vertex  B  is  in  the  circumference  and 
subtended  by  the  chord  B  G,  is  equal  to  half  the  central 
angle  BOG,  subtended  by  the  same  chord  B  G. 

5.  Equal  chords  subtend  equal  angles  at  the  center  of  a 
circle  and   also    at    the    circumference,    if  the  angles  are 


642  SURVEYING. 

inscribed  in  similar  segments.    Tlius,  i(  B,G,  G  H,  H  K,  and 
/:  Care  equal,  B  O  G=  GO  iT'and  G  B  H  =  H  B  K. 

6.  The  angle  of  intersection  of  two  tangents  equals  the 
central  angle  subtended  by  the  chord  uniting  the  tangent 
points.     Thus,  the  angle  C  E  F=  B  O  C. 

1  248.  Deflection  Angeles. — When  two  lines  meet  in 
the  same  plane,  they  are  said  to  form  an  angle,  and  the  point 
of  meeting  is  called  the  angular  point.  The  rate  of  diver- 
gence or  deflection  of  the  two  lines  from  their  common  or 
angular  point  determines  the  size  of  the  angle.  The  unit 
of  angular  measurement  is  the  degree,  equal  to  g-^  part  of  a 
circle.  Two  lines  forming  an  angle  of  one  degree  with  each 
other  will,  at  a  distance  of  one  hundred  feet  from  the  angular 
point,  deflect  or  diverge  1.745  feet. 

In  Fig.  280,  the  lines  A  B  and  A  C,  meeting  at  the  point 
A,  are  supposed  to  form  an  angle  of  1°,  and  the  angle  BAG 
is  measured  by  the  arc  B  C,  described  with  the  radius  A  B, 


Fig.    280. 

which  is  100  feet  in  length.  The  arc  B  C  and  the  straight 
line  joining  the  extremities  of  that  arc,  i.  e.,  the  chord  B  C, 
are  assumed  to  be  of  equal  length. 

1249.  Degree  of  Curvature. — The  curve  from 
which,  as  a  unit  or  basis,  all  other  railroad  curves  are 
deduced,  is  called  a  one-degree  curve.  It  is  the  circum- 
ference of  a  circle  whose  radius  is  5,730  feet,  or,  more  exactly, 
6,729.05  feet,  in  length.  Two  radii  forming  an  angle  of  one 
degree  at  the  center  of  a  one-degree  curve  will  subtend  a 
chord  of  100  feet  at  its  circumference.  The  arc  subtended 
by  this  chord  of  100  feet  is  assumed  to  be  of  the  same  length 
as  the  chord. 

In  Fig.  281,  let  A  B  and  A  C  he  radii  5,729.05  feet  in 
length,  forming  an  angle  of  1°  at  the  center  A  ;  then  the  arc 
B  C  subtended  by  these  radii  will  be  100  feet  in  length.  The 
curve  B  Ci^  called  a   1°  curve.     If,  from  the  point  (?  as  a 


SURVEYING. 


643 


center,  with  a  radius  O  B  equal  to  2,864.93  feet,  we  describe 
an  arc  B  D  100  feet  in  length,  the  radii  O  B  and  O  D  will 


Bz5729,^LSi 


Fig.  281. 


form  an  angle  of  2°  at  the  center  O,  and  the  curve  B  D  is 
called  a  2°  curve.  A  curve  whose  radius  is  nearly  one-third 
A  B,  or  1,910.08  feet,  is  a  3°  curve,  etc. 

The  deji^ree  of  a  curve  is  determined  by  the  central 
angle,  which  is  subtended  by  a  chord  of  100  feet.  Thus,  if 
B  O  G  {Fig.  282)  is  10°  and  B  G  is  100  feet,  B  G  H  K  C  is 
a  10°  curve. 


Fig.  288. 


The  deflection  an^le  of  a  curve  is  the  angle  formed  at 
any  point  of  the  curve  between  a  tangent  and  a  chord  of  100 
feet.     The  deflection  angle  is,  therefore,  balf  the  degree 


044  SURVEYING. 

of  the  curve.  Thus,  if  the  chord  B  G  is  100  feet,  the  angle 
E  B  G  is  the  deflection  angle  of  the  curve  B  G  H  K  C,  and  is 
half  the  angle  B  O  G. 

Example.— Given  the  deflection  angle  EB  G  =  D  (Fig.  283),  to  find 
the  radius  ^  C>  = /?. 

Solution. — Draw  O  Z  perpendicular  to  B  G.     In  the  right-angled 

triangle  B O L,    we  have  sin  BOL  =  ^^;  hut  BO  L  =  E B  G  =  D, 

since  OL  being  perpendicular  to  the  chord  B  G  it  bisects  the  arc 

BLG.     But  the  angle  Z>  =  ij5(?G;  hence,  angle  i5C>Z=  A     BL=z 

50  feet  and  the  radius  BO  =  R.     Substituting  these  values  in  the 

50 
given  equation,  we  have  sin  D  — —\  whence,  j^  sin  /?  =  50,  and  we 

have  the  formula 

^  =  7iF3-  (89-) 

For  curves  of  from  1°  to  10°,  the  radius  may  be  found  by  dividing 
5,730  ft.  (the  radius  of  a  1°  curve)  by  the  degree  of  the  curve.  The  re- 
sults obtained  are  sufficiently  accurate  for  all  practical  purposes.  For 
sharp  curves,  i.e.,  for  those  exceeding  10°,   the  above  formula,  viz., 

50 
R  —  —. — =;  should  be  used,  especially  if  the  radii  are  to  be  used,  as  a 
sm  Z> 

basis  for  further  calculation. 

For  example,  the  radius  of  a  4°  curve  is  found  by  both  methods  as 

follows:     By  first  method,    /?  =  5,730  ft. -5- 4  =  1,433.5  ft.     By  second 

method,  we  find  the  deflection  angle  Z>  of  a  4°  curve  is  2°.     Applying 

the  formula,  R  =  -^~-^,  we  have  R  =  -—rr  =  1,432.67  ft. 
sm  Z>  .0349 

In  this  case  the  error  is  only  .27  foot,  and  may  be  ignored  in  prac- 

5  730 
tical  work.     For  a  30°  curve  we  have  by  first  method,  R  =   '  .     =191 

50  50 

ft.    By  second  method,  we  have  R  =  -: — r^^  =  ^..^^^  =  193.18  ft.      In 
■^  sm  15        .25882 

this  case  the  error  is  2.18  ft.,  and  the  error  increases  as  the  degree  of 

curve  increases. 

The  radii  given  in  the  table  of  Radii  and  Deflections  are  calculated 

.      r  .      „  50 

by  the  formula  R  =  —. — j^. 
■'  sm  D 

1250.     Sub-Chords  for  Curves  of  Short  Radii.— 

On  curves  of  short  radii,  i.  e.,  curves  of  20°  and  upwards, 
center  stakes  are  driven  at  intervals  of  25  feet.  In  Art. 
1248,  we  stated  that  the  standard  chord  and  arc  are  as- 
sumed to  be  of  the  same  length.     This  is  practically  true 


SURVEYING.  G45 

for  curves  of  large  radii,  but  for  curves  above  20°  the  excess 
of  length  of  arc  over  the  chord  constantly  increases.  If, 
now,  in  Fig.  282,  the  chord  B  C  is  100  feet  in  length,  the  arc 
B  G  H  K  C  must  be  greater  than  100  feet;  and  if  the  arcs 
B  G,  G  H,  H  K,  and  K  C  are  equal,  i.  e. ,  each  equal  to  one- 
quarter  the  arc  B  H  C,  then  the  equal  chords  B  G,  G  H, 
H  K,  and  K  C  subtending  these  equal  arcs  must  each  be 
greater  than  one-quarter  of  B  C,  which  we  assumed  to  be 
100  feet.  These  greater  chords  must,  therefore,  be  greater 
than  25  feet.  Suppose  the  curve  B  H  C  to  be  a  20°  curve, 
and  the  chord  B  C,  100  feet ;  then  the  central  angle  B  O  C 
is  20°.     As  the  arc  B  G  is  one-quarter  of  the  arc  B  H  C,  the 

20° 
central  angle  B  O  G  \s  ~    =  5°.     The  line  O  L,  drawn  to 

the  middle  point  of  the  chord  B  G,  is  perpendicular  to  B  G 
and  bisects  the  angle  BOG.  The  deflection  angle  E  B  G  = 
B  O  L  ^  G  O  L.  Let  C  designate  the  chord  B  (7,  7?,  the 
radius  O  B  and  D,  the  deflection  angle,  E  B  G  =  B  O  L. 
In  the  right-angled  triangle  B  O  L,  we  have  sin  B  O  L  = 

L>     T 

-fTj)-     Substituting  the  above   given   values,   we  have   sin 

1  (^ 
D  =  ^^jT-,  whence  \  C  ^^  R  sin  D,  and  we  have 

C=1  RsmD.  (90.) 

The  central  angle  for  the  chord  B  G  is  5°.     The  deflection 

angle   D  is,    therefore,   |°  =  2°  30'.     Sin  2°    30'  =■  .04362. 

Since  the  deflection  angle  E  B  C  =  10°  for  this  case,  R  =■ 
50  ^  sin  10°  =  287.94  ft.  Hence,  chord  6"  =  2  X  287.94  X 
.04302  =  25.12  ft. 

Accordingly,  in  measuring  the  short  chords,  25.12  feet 
should  be  used  instead  of  25  feet. 

1251.  Tangent  Distances. — When  an  intersection 
of  tangents  has  been  made  and  the  intersection  angle  meas- 
ured, the  next  question  is  the  degree  of  curve  which  is  to 
unite  them,  which  being  decided,  the  next  step  in  order  is 
the  location  of  the  points  on  the  tangents  where  the  curve 


640  SURVEYING. 

* 

begins  and  ends.     These  two  points  are  equally  distant  from 

the  point  of  intersection  of  the  tangents,  which  is  called  the 

P.  I.     The  point  where  the  curve  begins  is  called  the  point 

of  curve,  or  the  P.C. ;  the  point  where  the  curve  terminates 

is  called  the  point  of  tangent,  or  the  P.  T.     The  distance 

of  the  P.  C.  and  P.  T.  from  the  P.  I.  is  called  the  tangent 

distance. 

In  Fig.  282,  let  A  B  and  C  Dht,  tangents  intersecting  at 

the  point  E  and  forming  an  angle  C  E  F=^  40°  00'  with  each 

other.     It  is  decided  to  unite  these  tangents  by  a  10°  curve 

whose  radius  is  573.7  feet.     Call  the  angle  of  intersection  /, . 

the  radius  B  O,  R,  and  the  tangent  distance  B  E,  T.    From 

Art.  1247,  proposition  6,  we  have  B  O  C=  C  £  F;  hence, 

the  angle  B  O  E  =  ^  C  E  F.  From  the  right  triangle  E  B  O 

BE 

we  have  tan  B  O  E  =  -75-7^. 

x>  U 

T 

Substituting  the  above  equivalents  we  have  tan  ^  /=  -p, 

whence  T  =  R  tzn  ^  F.  (91.) 

In  our  example  R  =  573. 7  f  t. ;  ^  /  =  20° ;  tan  20°  =  .  36397. 
573.7  X  .36397  =  208.81  ft.  Measure  back  from  the  point  E 
on  both  tangents  the  distance  208.81  ft.  to  the  points  B  and 
C.  Drive  plugs  flush  with  the  ground  at  both  points  and 
set  accurate  center  points,  marked  by  tacks,  in  both.  Di- 
rectly opposite  each  of  these  plugs  drive  a  stake  called  a 
guard  stalce,  because  it  guards  or  rather  indicates  where 
the  plug  is.  The  stake  at  B,  if  the  numbering  of  the  stations 
runs  from  B  towards  C,  will  be  marked  P,  C,  and  the  stake 
at  C  marked  P.  T. 

1252.     To  Lay  Out    a    Curve  With  a  Transit.— 

Having  set  the  tangent  points  B  and  C,  Fig.  282,  set  up 
the  transit  at  />,  the  P.  C.  Set  the  vernier  at  zero  and 
sight  to  E,  the  intersection  point.  Suppose  B  to  be  an  even 
or  "full  station,"  "say  18,  and  that  it  has  been  decided  to 
set  stakes  at  each  hundred  feet.  Let  the  central  angle 
B  O  6\  measured  by  the  100-feet  chord  B  G,  be  10°;  then, 
the  deflection  angle  E  B  G,  whose  vertex  B  is  in  the  circum- 


SURVEYING.  647 

ference  and  subtended  by  the  same  chord  B  G,  will  be  ^ 
B  O  G  ox  5°.  Turn  an  angle  of  5°  from  B,  which  in  this 
case  will  be  to  the  right;  measure  a  full  chain,  100  feet, 
from  B  and  line  in  the  flag  at  G  ;  drive  a  stake  at  6",  which 
will  be  marked  19.  Turn  off  an  additional  5°  making  10° 
from  zero,  and  at  the  end  of  another  chain,  at  //,  set  a  stake 
marked  20.  Continue  turning  deflections  of  5°  until  20°  or 
one-half  of  the  intersection  angle  is  reached.  This  last 
deflection,  if  the  work  has  been  correctly  done,  will  bring 
the  head  chainman  to  the  point  of  tangent  C.  It  is  but 
rarely  that  the  P.  C.  comes  at  a  full  station.  When  the 
P.  C.  comes  between  full  stations  it  is  called  a  sub- 
station, and  the  chord  between  it  and  the  next  full 
station  is  called  a  sub-chord.  Had  the  P.  C.  of  the  curve 
come  at  the  sub-station,  say  17  +  32,  the  deflection  for  the 
sub-chord  of  100  —  32  or  68  feet,  the  distance  to  the  next 
station,  is  found  as  follows:  The  deflection  for  a  full  station, 
i.  e.,  100  feet,  is  5°  =  300',  and  the  deflection  for  1  foot  is 

1^  =  3',  and  for  68  feet  the  deflection  will  be  68  X  3  =  204'  = 

3°  24',  which  is  turned  off  from  zero  and  a  stake  set  on 
line,  68  feet  from  the  transit,  at  Station  18.  The  length  of 
a  curve  uniting  two  given  tangents  whose  intersection  angle 
is  determined,  is  found  as  follows: 

Suppose  /  =  32°  40',  and  that  the  tangents  are  to  be  united 
by  a  6°  curve ;  32°  40'  reduced  to  the  decimal  form  is  32.666° ; 
as  each  central  angle  of  6°  will  subtend  a  100-foot  chord,  or 
one  chain,  there  will  be  as  many  such  chords  or  chains  as  6 
is  contained  times  in  32.666,  which  is  5.444,  that  is,  there 
will  be  5.444  chains  in  the  curve,  or  544.4  feet,  which  is  the 
required  length  of  the  curve.  The  P.  C.  and  P.  T.  having 
been  set  and  the  station  of  the  P.  C.  determined  by  actual 
measurement,  say  58  +  71,  the  station  of  the  P.  T.  is  found 
by  adding  to  58  +  71,  the  station  of  the  P.  C,  the  calculated 
length  of  the  curve,  544. 4  feet.  58  +  71  +  544. 4  =  64  +  15. 4, 
the  station  of  the  P.  T. 

Another  method  of  calculation  is  the  following:  The  sum 
of  all  the  deflection  angles  is  equal  to  one-half  the  intersection 


648  SURVEYING. 

angle.       The    intersection    angle    being    32°  40',   one-half 
equals  10°  20',  which,  reduced  to  minutes,  equals  *.»8()'.      The 

deflection  for  100  feet  is  -°  =  3°  =  180',   and  the  deflection 

Z 

180 
for  1  foot  ^s—-'  =  1.8';  then,  980',  the  total  deflection,   di- 
vided by  1.8',  gives  544.4   feet,  the  required   length  of  the 
curve. 

EXAMPLES   FOR  PRACTICE. 

In  the  following  examples,  let  /=  angle  of  intersection,  7"  =  tan- 
gent, and  L  =  length  of  curve. 

1.     /=  16°  13',  degree  of  curve  =  3°,  required,  7" and  L. 

Ans.j  ^=272.13  ft. 
(  L  =  540.55  ft. 
3.     /=  59°  20',  degree  of  curve  =  8°  30',  required,  T'and  L. 

Ans  \  ^'=384.32  ft. 
^"'-  \  L  =  698.04  ft. 

3.  /=  21°  35',  degree  of  curve  =  4°  15',  required,  7"  and  L. 

Ans  \  7^=257.03  ft. 
^"'-  I  Z  =  507.84  ft. 

4.  The  degree  of  a  curve  is  5°  30' ;  what  is  the  deflection  angle  for 
a  chord  of  16.2  feet  ?  Ans.  26.7'. 

5.  The  degree  of  a  curve  is  7°  15' ;  what  is  the  deflection  angle  for  a 
chord  of  38.4  feet  ?  Ans.  1°  23^'. 

1253.  Obstructions  in  tlie  Line  of  Curve. — Fre- 
quently it  happens  that  the  entire  curve  can  not  be  run  in 
from  the  P.  C.  on  account  of  obstructions.  This  is  especi- 
ally the  case  in  either  hilly  or  wooded  country,  and  the 
transit  has  to  "move  up"  to  an  intermediate  point.  For 
example,  in  Fig.  282,  we  will  suppose  that  Station  //,  200 
feet  from  B,  is  the  last  point  which  can  be  set  from  the 
P.  C.  at  B.  A  plug  is  driven  at  //  flush  with  the  ground 
and  carefully  centered,  and  a  tack  driven  at  the  point.  The 
deflection  angle  E  B  H  is  10°  to  the  right.  The  transit  is 
set  up  at  //,  an  angle  of  10°  to  the  left  is  laid  off  from  zero, 
and  the  vernier  clamped.  The  instrument  is  then  sighted 
to  a  flag  at  />,  the  spindle  clamped,  and  a  close  sight  to  the 
flag  taken,  the  lower  tangent  screw  being  used  to  adjust  the 
sight.     The  vernier  clamp  is  then  loosened  and  the  vernier 


SURVEYING. 


649 


set  at  zero.  The  line  of  sight  will  then  be  on  a  tangent  to 
the  curve  at  H^  and  the  deflection  angles  to  K  and  C  can  be 
laid  off  as  before  and  the  stations  K  and  C  located. 

1 254.  Tangent  and  Chord  Deflections.— Let  A  B 

in  Fig.  283  be  a  tangent,  and  B  C  E  H  2i  curve  commencing 
at  B.  Produce  the  tangent  A  B  to  the  point  D.  The  line 
C  D  vs,  2i  tangent  deflection,  and  is  the  perpendicular 
distance  from  the  tangent  to  the  curve.  If  the  chord  B  C 
be  produced  to  the  point  6",  making  CG^=BC=^C  E,  the 
distance  G  E  is  2i  chord  deflection  and  is  double  the 
tangent  deflection  D  C. 

1255.  Given  the  radius  B  O  =  R,  Fig.  283,  to  find  the 
chord  deflection  E  G  and  the  tangent  deflection  C  D  =  E  E. 


^ 


Fig.  283. 


The  triangles  O  C  E  and  C  E  G  are  similar,  since  both 
are  isosceles,  and  the  angle  G  C  E  =  angle  C  O  E.     Hence, 


050 


SURVEYING. 


we  have  O  C  '.  C  E::C  E  \  E  G.  Denoting  the  chord  C  E 
by  c  and  the  chord  deflection  E  G  by  d^  we  have,  from  the 
above  proportion,  R  \  cv.c  \  d.     Therefore, 


ri         ^ 

^=-^. 


(92.) 


To  find  the  tangent  deflection,  draw  C  E  to  the  middle 
point  of  E  G.  By  Art.  1254,  E  E  =  D  C  =  the  tangent 
deflection.  Hence,  tangent  deflection  =  one-half  the  chord 
deflection,  from  which 

tangent  deflection  = --75.  (93.) 

1256.  Practical  Method  of  Determining  Tan- 
gent and  Chord  Deflections. — Let  it  be  remembered  for 
a  basis  of  calculation  that  the  chord  deflection  for  a  one- 
degree  curve,  the  chord  being  100  feet  in  length,  is  1.745 
feet;  for  a  2°  curve,  double  the  deflection  for  a  1°  curve,  or 
3.49  feet,  and  so  on.  The  tangent  deflection  being  one-half 
the  chord  deflection,  for  a  1°  curve  it  will  be  .873  foot,  for 
a  2°  curve  it  will  be  1.745  feet,  etc. 

Distances  measured  either  on  chords  or  tangents  are 
expressed  in  decimal  parts  of  a  station,  which  is  100  feet,  and 


Pig.  284. 


is  assumed  as  1.  Thus,  the  tangent  deflection  for  75  feet 
will  be  expressed  as  the  tangent  deflection  for  .75  of  a 
station.     This  expression  is,  however,  confined  entirely  to 


SURVEYING.  G51 

the  calculation,  and  is  spoken  of  as  the  tangent  deflection  for 
75  feet.  Fig.  284  will  be  used  to  demonstrate  the  principle 
upon  which  tangent  deflections  are  based. 

Let  A  B  he  a.  tangent,  and  B  the  P.  C.  of  a  2°  curve  to 
the  right.  We  determine  the  chord  deflection  for  100  feet 
chord  of  a  2°  curve  to  be  3.49  feet.  The  tangent  deflection 
is  one-half  the  chord  deflection,  or  1.745  feet. 

Let  B  C  =  100  feet,  a  full  station  (which  express  as  1), 
then  CL,  the  tangent  deflection  at  C,  will  =  1.745  feet,  for, 
since  this  is  a  2°  curve,  the  chord  deflection  =  1.745  X  2,  and 

the  tangent  deflection  =  — — =  1.745  ft. 

To  find  the  tangent  deflection  for  any  intermediate  point 
G,  75  ft.  from  B,  express  the  distance  as  a  decimal  of  the 
full  station,  or,  in  this  case,  .75.  Square  the  decimal  thus 
formed,  and  multiply  by  the  tangent  deflection,  in  this  case, 
1.745;  the  result  Avill  be  the  tangent  deflection  for  the  point 
considered.  Thus,  the  tangent  deflection  for  the  point  is 
the  line  G  K,  and  the  length  of  6^  A^  =  . 75"  X  1.745  ==.562  X 
1.745:=  .981  ft. 

For  the  point  /?,  125  ft.  from  B,  the  tangent  deflection  is 
D  M,  and  the  length  of  D  M  is  found  as  above.  Thus,  to 
express  125  as  a  decimal  of  a  full  station,  divide  125  by 
100,  obtaining  1.25.  Then  1.25"  X  1.745  =  1.562  X  1.745  = 
2.725  ft. 

In  the  above,  we  have  assumed  that  the  chord  and  the 
corresponding  tangents  were  of  equal  length;  i.  e.,  that 
B  1=  B  F,  B  K—  B  G,  etc.  This  is  not  strictly  true,  but 
is  near  enough  for  all  practical  purposes,  particularly  when 
the  degree  of  the  curve  is  small. 

1257.     Laying  Out  Curves  Without  a  Transit.— 

During  construction,  the  engineer  is  often  called  upon  to 
restore  center  stakes  on  a  curve  when  the  transit  is  not  at 
hand.  With  the  aid  of  a  tape  and  a  few  stakes  for  lining  in, 
a  line  can  be  run  closely  approximating  the  true  one,  by 
applying  the  principle  demonstrated  in  Art.  1256. 

A   practical   application   of    this   principle   is    shown   in 


G52 


SURVEYING. 


Fig.  285,  in  which  A  B  is  a  tangent,  B  the  P.  C.  of  a  4° 
curve  RK  The  chord  deflection  of  a  4°  curve  for  100  feet 
chord  is  G.98  ft.  The  tangent  deflection  =  \  the  chord 
deflection,  is  3.49  ft.  Let  B  =  Sta.  8  +  25,  a  stake  at  each 
full  station  on  the  curve  being  required.  Restore  the 
stakes  at  A  and  B,  which  will  determine  the  P.  C,  and  give 
the  direction  of  the  tangent  A  B.  The  distance  from  the 
P.  C.  to  the  next  full  station  C  is  75  feet  or  .75  of  a  full 
station;  .75*  X  3.49  =  .502  x  3.49  =  1.9G  ft.,  the  tangent 
deflection  at  C.  The  engineer  being  without  a  transit,  the 
point  C  is  found  by  measuring  75  feet  from  B  and  setting  a 
stake  at  C  in  line  with  a  stake  at  B,  the  P.  C,  and  a  point 
A  B         C 


Pig.  285. 

on  the  tangent  ^  .5  as  A.  With  a  tape,  measure  the  dis- 
tance 1.9G  ft.  from  C  at  right  angles  to  B  C,  and  drive  a 
stake  at  that  point  /%  which  will  be  Station  9.  Measure 
100  feet  from  F  and  set  a  point  at  D  in  the  line  B  F.  By 
previous  calculation,  we  know  the  chord  deflection  for 
100  feet  is  G.98  ft.  Measure  the  distance  6.98  ft.  at  right 
angles  to  the  line  FD  and  drive  a  stake  at  G,  which  will 
be  Station  10.  In  like  manner  set  the  remaining  Station  11, 
which  is  previously  known  to  be  the  P.  T.  Although  the 
chord  deflection  Z^  C  is  not  theoretically  at  right  angles  to 
F D,  yet  D  G  is  so  small  compared  with  FD  that  for  curves 
of  ordinary  degree  the  offset  is  made  at  right  angles. 


SURVEYING.  653 

EXAMPLES  FOR  PRACTICE. 

1.  The  degree  of  curve  is  5",  the  chord  67  ft. ;  what  are  the  tangent 
and  chord  deflections  ?         .  .        ^  Tan  def.    =1.959  ft. 

"^' "I  Chord  def.  =  3.918  ft. 

2.  The  degree  of  curve  is  7^  30',  the  chord  23.5  ft. ;  what  are  the 
tangent  and  chord  deflections  ?  .        \  Tan  def.    =  .359  ft. 

"^'  1  Chord  def.  =  .718  ft. 

3.  The  degree  of  curve  is  6"  15',  the  chord  117  ft. ;  what  are  the 
tangent  and  chord  deflections  ?  .        (  Tan  def.    =    7.465  ft. 

"^'  1  Chord  def.  =  14.930  ft. 


1258.  To  Determine  Degree  of  Curve  by  Meas- 
uring a  Middle  Ordinate. — In  track  work,  it  is  often 
necessary  to  know  the  degree  of  a  curve  when  no  transit  is 
available  for  measuring  it.  The  degree  can  be  found  by 
measuring  the  middle  ordinate  of  any  convenient  chord,  and 
multiplying  its  length  by  8,  which  will  give  the  chord  deflec- 
tion for  that  curve. 

Let  A  B,  in  Fig.  286,  be  a  50-foot  chord,  measured  on  the 
track,  and  let  the  middle  ordinate  ^  <^  be  .44  ft.  .44  X  8  = 
3.53  =  chord  deflection  for  6.44' 

50',   which,    expressed    in   ^. 
decimal  part  of  a  full  sta-  50' 

tion,  is.5;  .5' =  .25.     The  fig.  286. 

chord  deflection  for  100  feet  multiplied  by  .25  =  the  chord 
deflection  for  50  feet,  which  we  know  by  calculation  to  be 
3.52  feet.  Hence,  3.52-^.25  =  14.08  ft.,  the  chord  deflec- 
tion for  100  feet,  which,  divided  by  1.745,  the  chord  deflec- 
tion for  a  1°  curve,  gives  a  quotient  of  8.07,  nearly.  The 
inference  is  that  the  curve  is  8°. 


EXAMPLES   FOR   PRACTICE. 

1.  Length  of  chord  is  50  ft.,  middle  ordinate  .35  ft. ;  required,  de- 
gree of  curve.  Ans.  6°  25.08'. 

(The  original  curve  probably  6'  30.) 

2.  Length  of  chord  40  ft.,  middle  ordinate  .21  ft. ;  required,  degree 
of  curve.  Ans.  6'  1.02'. 

(The  original  curve  probably  6°.) 

3.  Length  of  chord  25  ft.,  middle  ordinate  .22  ft. ;  required,  degree 
of  curve.  Ans.  16°  8.28 . 

(The  original  curve  probably  16".) 


G54 


SURVEYING. 


1259.  Field  Books. — To  facilitate  the  field  work  of 
the  engineer,  field  books  have  been  published.  They  are 
portable,  being  carried  in  the  pocket,  and  contain,  in  con- 
densed form,  general  directions  for  the  conduct  of  field  work, 
together  with  all  the  necessary  data  in  the  form  of  tables, 
for  prosecuting  such  work  with  accuracy  and  dispatch. 

One  of  the  first  published  in  America  is  the  work  of  John 
B.  Henck,  to  whom  most  American  engineers  are  under 
obligation. 

1 260.  Note  Books. — Various  styles  of  note  books  are 
published,  the  pages  being  ruled  to  suit  the  particular  kind 
of  work  being  done.  They  are  of  three  classes,  viz.,  transit, 
level,  and  topography  books.  The  latter  are  ruled  in  squares, 
which  may  be  given  any  desired  scale  and  greatly  facilitate 
the  accurate  platting  of  topography  in  the  field. 

1261.  How  to  Keep  Transit  Notes. — 

A  good  form  for  location  notes  is  the  following: 


SutUm, 

OifltclioH 

IU.An9U 

M»f.  Bemrinf. 

De4.  Btmring. 

Bern 

June  90. 1994 
trk*. 

0 

9 

T 

«i*S 

4°54'e.T 

tfiX/ 

if.as'io'g. 

tr.  afia'g. 

t-no 

4''00' 

^ 

* 

9°00' 

■ 

""V       ffi^^ 

9-Hm 

9'00' 

4*80 

^^••' 

« 

t°OV 

S*40 

$«^»" 

4*90 

»•«»' 

S°W 

4 

*■>»«' 

I»t.AufU-iS°00' 

4'Cun*V 

*HU> 

o-w 

T.-19>i.9t  ft. 

Dtf.  Amflt  f*r  aOfttfOO 

9**0 

f.C4°M* 

r.Ci-3*90 

D*f.AmfUf»r  tft.-l.r 

9 

L»»0a  •/  0mrmt-9nft 

9 

r.l>4*05 

1 

O 

-. 

a.9ois'M. 

11.90°  tS"*. 

In  the  first  column  the  station  numbers  are  recorded. 
In  the  second  column  are  recorded  the  deflections  with  the 
abbreviations  P.  C.  and  P.  T.,  together  with  the  degree  of 
curve  and  the  abbreviation  R'  or  IJ,  according  as  the  line 
curves  to  the   right  or  left.     At  each  transit  point  on  the 


SURVEYING.  655 

curve,  the  total  or  central  angle  from  the  P.  C.  to  that 
point  is  calculated  and  recorded  in  the  third  column.  This 
total  angle  is  double  the  deflection  angle  between  the  P.  C. 
and  the  transit  point.  In  the  above  notes,  there  is  but  one 
intermediate  transit  point  between  the  P.  C.  and  the  P.  T. 
The  deflection  from  the  P.  C.  at  Sta.  3  +  20  to  the  inter- 
mediate transit  point  at  Sta.  4  +  50  is  2"  36'.  The  total 
angle  is  double  this  deflection,  or  5°  12',  which  is  recorded 
on  the  same  line  in  the  third  column.  The  record  of  total 
angles  at  once  indicates  the  stations  at  which  transit  points 
are  placed.  The  total  angle  at  the  P.  T.  will  be  the  same 
as  the  angle  of  intersection,  if  the  work  is  correct.  When 
the  curve  is  finished,  the  transit  is  set  up  at  the  P.  T., 
and  the  bearing  of  the  forward  tangent  taken,  which  affords 
an  additional  check  upon  the  previous  calculations.  The 
magnetic  bearing  is  recorded  in  the  fourth  column,  and  the 
deduced  or  calculated  bearing  is  recorded  in  the  fifth 
column. 

1 262.  Preservation  of  Notes  and  Records. — Notes 
should  never  be  erased.  If,  on  account  of  error  or  change  of 
plan,  they  should  cease  to  be  of  any  value,  they  are  crossed 
out,  i.  e.,  two  diagonals  are  drawn  across  the  page.  All 
notes  of  permanent  location  should  be  copied  each  day  into 
a  separate  book  for  office  reference,  to  prevent  confusion, 
and  for  record  in  case  the  original  notes  should  be  lost. 


LEVELING. 

1263.  A  Level  Surface. — A  level  surface  is  one 
parallel  to  the  surface  of  standing  water.  A  water  surface, 
though  not  theoretically  level,  owing  to  the  curvature  of 
the  earth's  surface,  is  assumed  to  be  level  and  perpendicular 
to  a  vertical  line,  or  the  line  of  gravity. 

The  height  of  a  point  is  its  distance  above  a  given  level 
surface,  measured  on  a  vertical  line,  and  is  called  its 
elevation.  The  process  by  which  the  elevation  of  a  point 
is  determined  is  called  leveling. 


65G  SURVEYING. 

1264.  Tlie  Three  Processes  of  Determining: 
Elevations. 

They  are  :   1st.     By  direct  leveling. 

2d.     By  indirect  leveling  ;   and 
3d.     By  barometric  leveling. 

1265.  Direct  Leveling. — In  the  process  of  direct 
leveling,  a  level  line  either  actual  or  visual  is  prolonged  so 
as  to  pass  directly  over  or  under  the  given  point  whose  eleva- 
tion is  required.  The  elevation  of  any  other  point  being 
determined  in  the  same  way,  the  difference  in  the  elevations 
of  the  two  points  is  found  by  subtracting  the  elevation  of 
the  lower  from  the  elevation  of  the  higher. 

1266.  Indirect  Leveling. — In  the  process  of  indirect 
leveling,  elevations  are  determined  by  means  of  lines  and 
angles. 

1267.  Barometric  Leveling. — In  barometric  level- 
ing the  elevation  of  a  point  is  determined  by  the  weight  of 
the  atmosphere  at  that  point  as  registered  by  a  barometer. 
The  second  and  third  processes  will  be  explained  later. 


DIRECT  LEVELING. 

1268.  General  Principles. — Direct  leveling  depends 
upon  three  principles,  two  of  which  have  already  been 
stated,  viz. :  First,  that  the  surface  of  a  liquid  in  repose  is 
level;  second,  that  a  vertical  line  is  perpendicular  to  that 
surface,  and,  third,  that  a  bubble  of  air  confined  in  a  vessel 
otherwise  filled  with  liquid  will  rise  to  the  highest  point  of 
that  liquid.  A  common  application  of  the  third  principle  is 
seen  in  the  spirit  level  used  by  carpenters  and  the  level 
board  used  by  masons. 

1269.  The  "  Y  "  Level. — There  are  a  great  variety  of 
instruments  for  determining  elevations.  The  one  in  most 
general  use  is  the  "  Y  "  level,  shown  in  Fig.  287. 

This  instrument  consists  of  an  erecting  telescope  A  B, 
i.  e.,  one  which  shows  the  image  of  the  object  to  which  the 
telescope  is  directed  in  its  erect  or  natural  position,  resting  in 
Y-shaped  supports  C  and  D,  from  which  it  takes  its  name. 


SURVEYING. 


657 


The  line  of  sight,  or  collimation,  is  identical  to  that  in  the 
transit  explained  in  Art.  1225,  and  is  parallel  to  the  level 
E  F.  The  tube  containing  the  eyepiece  G  has  an  exterior 
ring  //,  which  is  milled  to  assist  the  hand  in  turning  the 
tube.  This  movement  adjusts  the  eyepiece  to  the  cross- 
hairs. The  object  glass  at  B  is  moved  in  or  out  by  the 
milled  headed  screw  A';  L  and  J/are  parallel  plates;  the  bar 
O  P  supports  the  Y's  and  revolves  on  a  spindle  which  is 


FIG.  287. 

clamped  by  the  screw  N.  By  means  of  the  tangent  screw  X, 
the  telescope  can  be  slowly  turned  horizontally.  The  tele- 
scope is  leveled  by  means  of  the  leveling  screws  F,  Q^  R,  and  S. 
The  level  is  supported  by  the  tripod  T.  The  cross-hairs  are 
of  either  platinum  wire  or  spider  threads,  and  are  fastened 
to  a  ring  which  is  held  in  place  by  capstan  screws  shown  at 
U,  and  their  movements  are  regulated  in  the  same  way  as 
the  movements  of  the  cross-hairs  of  the  transit  explained  in 
Art.  1225. 


fi58  SURVEYING. 

1270.  The  Bubble  Tube. — The  bubble  tube  is  of 
glass  bent  upwards  and  so  nearly  filled  with  alcohol  that  only 
a  bubble  of  air  remains,  which  is  always  at  the  highest  point 
in  the  tube.  This  tube  is  protected  by  a  brass  case,  which 
is  fastened  to  the  underside  of  the  telescope,  and  provided 
with  the  means  for  adjustment.  The  one  end  may  be  raised 
or  lowered  and  the  other  end  moved  horizontally.  Through 
a  slit  in  the  upper  side  of  the  case,  the  bubble  tube  is  seen. 
Directly  over  it  is  a  scale  graduated  in  both  directions  from 
zero,  which  is  over  the  center  of  the  tube. 

The  Y's  C  and  D  support  the  telescope,  which  is  held  in 
place  by  hinged  clasps,  or  clips,  as  they  are  called,  fastened 
by  carefully  turned  pins,  by  means  of  which  the  tele- ' 
scope  can  be  firmly  held  in  any  desired  position.  The  Y's 
rest  upon  the  bar  O  P,  to  which  they  are  fastened  by  lock- 
nuts,  the  one  above,  the  other  below,  the  bar,  for  raising  or 
lowering.  The  bar  revolves  upon  a  finely  turned  steel  spindle, 
resting  in  a  socket  of  bell  metal.  The  parallel  plates  L  and  J/ 
are  united  by  a  ball-and-socket  joint,  and  held  in  place  by  the 
leveling  screws  V,  Q,  R,  and  S. 

1271.  Adjustments. — The  first  thing  todo  in  prep- 
aration for  actual  leveling  is  to  make  the  adjustments  of 
the  instrument. 

There  are  three  adjustments,  as  follows: 

1.  To  make  the  line  of  collimation  parallel  to  the  bottoms 
of  the  collars,  or  rings,  on  which  the  telescope  rests. 

2.  To  make  the  plane  of  the  level  parallel  to  the  line. of 
collimation,  or  to  the  bottom  of  the  collars. 

3.  To  cause  the  bubble  to  remain  in  the  center  of  the  tube 
while  the  telescope  is  being  revolved  horizontally. 

1 272.  First  Adjustment. — To  make  the  line  of  colli- 
mation parallel  with  the  bottoms  of  the  collars. 

Plant  the  tripod  firmly ;  choose  some  distant  and  clearly 
defined  point,  the  more  distant  the  better  so  long  as  the 
sight  is  distinct.  Remove  the  pins  from  the  clips  and  clamp 
the  spindle,  bringing  the  intersection  of  the  cross-hairs  to 


SURVEYING.  659 

exactly  bear  on  the  ^point  by  means  of  the  tangent  screw. 
Revolve  or  turn  the  telescope  on  its  supports  through  one- 
half  a  revolution,  i.  e.,  until  it  is  bottom  side  up.  If  the 
intersection  of  the  cross-hairs  is  still  on  the  point  of  sight,  it 
proves  that  the  line  of  collimation  is  parallel  to  the  bottoms 
of  the  collars.  If,  however,  the  line  of  sight  is  no  longer  on 
the  point,  move  the  cross-hairs  by  means  of  the  capstan* 
headed  screws  over  one-half  the  space  which  measures  the 
apparent  error,  being  careful  to  move  them  in  the  opposite 
direction  to  that  in  which  it  would  appear  they  should  be 
moved.  The  apparent  error  is  double  the  real  error,  and  is 
explained  in  Fig.  288. 

Let  the  instrument  stand  at  A  and  sight  to  the  point  B^ 
and  suppose  that  when  the  telescope  has  been  revolved  half 
way  around,  the  point  B  appears  to  be  at  C,  then  will  the 

_4  n 


'      I      \  Fig.  288. 

distance  B  C  h(t  double  the  real  error,  and  the  true  line  of 
sight  will  be  at  D,  half  way  between  B  and  C.  Sometimes 
both  cross-hairs  are  out  of  adjustment  and  they  must  be 
moved  alternately  until  the  intersection  of  the  cross-hairs, 
i.  e.,  the  line  of  collimation,  will  pass  through  the  same 
point  throughout  a  complete  revolution  of  the  telescope. 

1273.  Second  Adjustment. — The  second  adjustment 
is  to  make  the  plane  of  the  level  parallel  to  the  line  of  colli- 
mation, or  to  the  bottoms  of  the  collars,  and  is  made  as 
follows: 

Remove  the  pins  and  open  the  clips;  place  the  telescope 
over  a  pair  of  leveling  screws  and  clamp  the  spindle.  Bring 
the  bubble  to  the  middle  of  the  tube  by  means  of  the  level- 
ing screws,  and  revolve  the  telescope  through  an  eighth  of  a 
revolution.  The  bubble  tube  will  stand  out  at  an  angle  with 
the  Y's.  If  the  bubble  runs  it  shows  that  a  vertical  plane 
passed  through  the  longitudinal  axis  of  the  bubble  tube  is 
not  parallel  to  a  vertical   plane  passed  through  the  line  of 


6G0  SURVEYING. 

collimation.  To  correct  the  error,  bring  the  bubble  nearly 
back  by  means  of  the  check  nuts  which  regulate  the  lat- 
eral movement  of  the  tube,  and  repeat  the  operation  until 
the  bubble  ceases  to  run  while  the  partial  revolution  is  made. 
To  complete  the  bubble  adjustment,  level  the  telescope  and 
take  it  out  of  the  Y's  and  turn  it  "end  for  end."  If  the 
bubble  remains  in  the  center  of  the  tube,  the  second  adjust- 
ment is  complete.  If  it  runs  to  one  end,  bring  it  half  way 
back  by  means  of  the  check  nuts  provided  for  raising  or 
lowering  one  end,  and  the  rest  of  the  way,  i.  e.,  to  the 
middle  of  the  tvibe,  by  means  of  the  leveling  screws.  Re- 
peat the  operation,  as  the  adjustment  can  rarely  be  made 
with  one  trial. 

1274,  Third  Adjustment,  sometimes  called  the 
*' Bar  Adjustment." — This  is  to  cause  the  bubble  to  re- 
main in  the  center  of  the  tube  while  the  telescope  is  being 
revolved  horizontally. 

Level  the  instrument,  using  both  sets  of  leveling  screws. 
Having  centered  the  bubble  carefully  with  one  pair  of  level- 
ing screws,  turn  the  telescope  until  it  stands  directly  over 
the  other  pair  of  leveling  screws.  If  the  bubble  runs,  bring 
it  half  way  back  by  means  of  the  locknuts  at  the  end  of  the 
level  bar  and  complete  the  leveling  with  the  leveling  screws. 
Repeat  the  operation,  as  two  or  three  trials  will  probably  be 
necessary  to  complete  the  adjustment,  so  that  the  bubble 
will  remain  in  the  center  of  the  tube  throughout  an  entire 
horizontal  revolution  of  the  telescope. 

The  adjustments  of  the  level  should  be  tested  every  day 
when  in  constant  use,  as  any  defect  in  them  will  detract 
from  the  value  of  the  work  done,  and  a  serious  defect  will 
necessitate  a  repetition  of  the  work. 

The  cross-hairs  are  placed  at  right  angles  to  each  other, 
one  of  which  should  be  vertical  and  indicate  to  the  leveler 
whether  the  leveling  rod  is  being  held  plumb.  If  the  verti- 
cal cross-hair  is  "out  of  plumb,"  adjust  it  by  loosening  the 
capstan  screws  which  hold  the  ring,  to  which  the  cross-hairs 
are  fastened.     Suspend  a  plumb-bob  at  a  suitable  distance 


SURVEYING. 


661 


from  the  level,  and  having  sighted  to  it,  tap  the  capstan 
screws  sufficiently  hard  to  cause  the  cross-hairs  to  move. 
In  this  way  the  vertical  hair  can  be  made  to  coincide  with 
the  plumb  line,  which  is  a  true  vertical. 

1275.  Sensibility. — The  sensibility  of  the  level  de- 
pends directly  upon  the  radius  of  the  curve  of  the  bubble 
tube. 

The  graduated  scale  placed  directly  over  the  bubble  tube 
measures  the  movement  of  the  bubble.  The  sensibility  of 
the  level  may  be  determined  as  follows:  Having  leveled 
the  instrument,  take  a  reading  on  the  rod  held  say  200  feet 
from  the  instrument.  Suppose  this  reading  to  be  5.61  feet; 
with  the  leveling  screws  cause  the  bubble  to  move  over  one 
division  of  the  scale.  Suppose  the  rod  then  reads  5. 03  feet. 
Denote  the  radius  of  the  bubble  by  x.  Fig.  289,  the  distance 


5.61' 


Fig.  289. 

of  the  rod  from  the  instrument  by  d,  the  difference  of  rod 
readings  by  /i,  and  the  movement  of  the  bubble  by  5.  From 
the  approximately  similar  triangles  we  have  h  :   S  ::  d  :  x. 


or  .03  :  .01 :: 200  :  x,  whence  x  = 
of  the  bubble  tube. 


2.00 
.02 


=  100  feet,  the  radius 


1276.  Use  and  Care  of  the  Level. — The  level 
should  not  be  used  in  rainy  weather  if  it  can  be  avoided. 
Moisture  obscures  the  lenses  and  is  otherwise  injurious  to 
the  instrument.  When  rain  is  unavoidable,  wipe  the  lenses 
frequently  with  a  soft  linen  handkerchief,  and  when  re- 
turned to  the  office  or  camp,  thoroughly  wipe,  finishing  with 
a  piece  of  dry  chamois  skin  and  place  in  a  warm,  dry  place 
so  that  every  particle  of  moisture  may  be  removed.     Never 


662 


SURVEYING. 


carry  the  level  with  the  spindle  clamped.  This  rule  is 
especially  important  when  working  in  a  wooded  country 
where  underbrush  is  dense.  When  undamped,  the  level 
turns  freely  upon  the  spindle  and  yields  readily  to  any  pres- 
sure. A  blow  which  would  inflict  no  injury  upon  an  uu- 
clampcd  instrument  might  seriously  damage  one  while 
clamped  and  rigid. 

X'il'l.  Poiiver  and  Definition. — The  power  of  a  tele- 
scope is  measured  by  the  apparent  nearness  to  which  the 
image  of  the  object  is  brought  to  the  eye  of  the  observer. 

The  definition  of  a  telescope  is  measured  by  the  degree  of 
clearness  of  the  outline  of  the  image. 

1278.  Target  Rods. — Target  rods  are  divided  into 
two  classes,  viz.,  those  which  are  self-reading,  or  speaking 
rods,  and  those  which  are  not  self-reading. 
Railroad  work  is  done  chiefly  with  a  self -reading 
rod.  That  in  most  general  use  is  called  the 
Philadelphia  rod,  and  is  shown  in  Fig.  290. 
It  is  in  two  sections  held  together  with  brass 
clamps  A  and  B,  one  section  sliding  over  the 
other.  When  closed,  the  rod  measures  7  feet, 
sliding  to  12  feet.  It  is  graduated  to  feet, 
tenths,  and  hundredths.  The  feet  are  marked 
in  large  red  figures,  half  above  and  half  below 
the  marks  of  division;  tenths  of  feet  are 
marked  in  black  figures  from  1  to  9,  the  lines 
of  division  reaching  half  way  across  the  face 
of  the  rod;  hundredths  are  marked  by  lines 
yijy  of  a  foot  in  width,  alternating  white  and 
black,  and  extending  about  one-third  the  way 
across  the  face  of  the  rod.  The  target  is  either 
circular  or  elliptical  and  divided  into  quarters, 
alternating  red  and  white.  The  division  lines 
are  so  arranged  that  when  the  rod  is  held  in  a 
vertical  position  one  of  them  will  be  horizontal 
Fig.  290.  and  the  other  vertical.  The  target  C  is  fast- 
ened to  a  collar  which  slides  up  and  down  the  rod,  and  is 


SURVEYING.  663 

fitted  with  a  screw  Z>,  which  clamps  it  at  any  desired  point. 
An  opening  more  than  one-tenth  of  a  foot  in  length  is  cut 
in  the  face  of  the  target.  A  vernier  is  fastened  to  the  target 
whose  zero  point  exactly  coincides  with  the  line  which 
divides  the  target  horizontally.  It  lies  within  the  opening, 
on  the  face  of  the  rod,  and  reads  to  thousandths  of  a  foot. 
To  prevent  wear,  the  foot  of  the  rod  is  shod  with  brass.  Rod 
readings  under  7  feet  are  usually  taken  with  the  two  sections 
closed,  and  the  target  moved  up  or  down  until  the  horizontal 
line  on  the  target  coincides  with  the  horizontal  cross-hair  of 
the  telescope.  When  readings  of  more  than  7  feet  are  taken, 
the  clamp  at  B  is  loosened  and  the  sliding  section  moved 
upwards  until  the  horizontal  line  of  the  target  and  the  hori- 
zontal cross-hair  of  the  telescope  coincide.  The  rod  is  then 
clamped,  and  is  called  a  long  or  higli  rod,  and  can  be 
read  to  thousandths  with  the  vernier  attached  to  the  collar 
at  B.  In  setting  the  target,  the  leveler  should  read  the  rod 
as  closely  as  he  can  with  the  level,  calling  the  reading  to  the 
rodman,  who  sets  the  target  at  the  given  reading  and  holds 
the  rod  up  for  a  check  reading.  Four  times  out  of  five 
the  leveler's  reading  will  be  the  correct  one,  even  to  thou- 
sandths. More  mistakes  are  made  in  reading  the  number  of 
feet  than  the  number  of  tenths.  The  leveler  by  first  calling 
the  reading  to  the  rodman  will  be  certain  to  prevent  such  an 
error,  as  it  would  at  once  be  detected  in  the  check  reading. 
An  experienced  rodman  can  hold  a  rod  practically  plumb, 
and  for  all  ordinary  work  his  care  is  considered  sufficient. 
For  work  requiring  the  greatest  possible  accuracy,  such. as 
bridge  foundations,  a  hand  level,  which  fits  closely  to  the 
angle  of  the  rod  and  carries  two  small  spirit  levels,  is  used  to 
accurately  plumb  it.  In  using  a  rod  which  is  not  self  reading, 
all  readings  are  taken  with  the  target. 

1279.  Examples  in  Direct  Leveling. — The  princi- 
ples of  direct  leveling  are  illustrated  in  Fig.  291. 

Let  A  be  the  starting  point,  which  has  a  known  elevation 
of  20  feet.  The  instrument  is  set  at  B^  leveled  up,  and 
sighted  to  a  rod  held  at  A .     The  target  being  set,  the  reading, 


664 


SURVEYING. 


8.42  feet,  called  a  backsight, 
is  the  distance  which  the  point 
where  the  line  of  collimation  cuts 
the  rod  is  above  the  point  A,  and 
is  to  be  added  to  the  elevation  of 
the  point  A.  20.00  +  8.42  =  28.42 
is  called  the  height  of  instrument 
and  designated  H.  I.  The  instru- 
ment being  turned  in  the  opposite 
direction,  a  point  C  is  chosen, 
which  must  be  below  the  line  of 
sight.  This  point  is  called  a  turn- 
ing point,  and  is  designated  by  the 
abbreviation  T.  P.  Drive  a  peg 
at  C  or  take  for  a  turning  point  a 
point  of  rock  or  some  other  perma- 
nent object  upon  which  the  rod  is 
held.  The  reading  at  this  point  is 
a  foresight,  and  is  to  be  sub- 
tracted from  the  height  of  the 
instrument  at  B  to  find  the  ele- 
vation of  the  point  at  C. 

Let  the  rod  reading  be  1.20  ft. 
As  this  reading  is  a   foresight,  it 
must    be   subtracted    from  28.42, 
the   height   of   instrument   at  B; 
28.42  -  1.20  =  27.22',  the  ele- 
vation of  the  point   C.     As 
the    ground    rises   abruptly, 
the  rodman  should  slide  the 
rod  to  its  full  length,  being 
careful    to    keep    it 
on   the   same  point 
C.    The  leveler  car- 
ries the  instrument 
to  D,  which  should 
o  be  of  such  a  height 
■^-^    above  C  that  when 


SURVEYING.  665 

leveled  up  the  line  of  sight  will  cut  the  rod  near  the  top. 
The  backsight  to  fT gives  a  reading  of  11. 5G  ft.,  which,  added 
to  27.22  ft.,  the  elevation  of  C,  gives  38.78  ft.,  the  height  of 
the  instrument  at  D.  The  rodman  then  goes  to  E,  a  point 
where  a  foresight  reading  is  1.35,  which,  subtracted  from 
38.78,  the  H.  I.  at  D,  gives  37.43  feet,  the  elevation  of  E. 
The  level  is  then  set  up  at  F,  being  careful  that  the  line  of 
sight  shall  clear  the  hill  at  L.  The  backsight  6.15  ft. 
added  to  37.43  ft.,  the  elevation  of  E,  gives  43.58  ft.,  the 
H.  I.  at  F.  The  rod  held  at  G  gives  a  foresight  of  10.90  ft., 
which,  subtracted  from  43.58,  the  H.  I.  at  F,  gives  32.68,  the 
elevation  at  G.  Again  moving  the  level  to  H,  the  backsight 
to  G  of  4.39  ft.  added  to  32.68,  the  elevation  of  G,  gives 
37.07  ft.,  the  H.  I.  at  H.  Holding  the  rod  at  A' a  foresight 
of  5.94  subtracted  from  37.07  gives  31.13,  the  elevation  of 
the  point  K.  The  elevation  of  the  starting  point  A  is 
20.00  ft.;  the  elevation  of  the  point  K '\s  found  by  direct 
leveling  to  be  31.13  ft.,  and  the  difference  in  the  elevations 
of  A  and  K  is  31.13  —  20.00  =  11.13  ft. ;  that  is,  the  point 
A' is  11.13  feet  higher  than  the  point  A. 

1280.  A  Datum  Line. — A  datum  line  is  the  base 
line  to  which  the  elevation  of  every  point  of  a  series  is  re- 
ferred. Thus,  in  Fig.  291,  the  datum  line  or  plaice  is  20  feet 
lower  than  the  point  A,  and  the  elevations  of  the  points 
A,  B,  C,D . . .  .K  are  their  elevations  above  this  datum  line. 
Such  a  series  of  elevations  is  called  a  line  of  levels. 

1281.  Turning  Points. — Turning  points,  men- 
tioned in  Art.  1279,  are  the  points  where  backsights  and 
foresights  are  taken.  The  backsights  are  plus  (-f-)  readings, 
and  are  to  be  added;  the  foresights  are  minus  (  — )  readings, 
and  are  to  be  subtracted.  The  rodman  should  make  a  peg 
of  well-seasoned  oak,  or  other  hard  wood,  about  9  inches  in 
length,  1  inch  in  diameter,  sharpened  at  one  end  and 
rounded  at  the  other  end,  which  is  the  turning  point.  For 
driving  the  peg  he  should  carry  in  a  leather  scabbard  a 
light  hatchet.  A  point  for  a  foresight  having  been  deter- 
mined, the  rodman  drives  the  peg  firmly  in  the  ground  and 


666 


SURVEYING. 


holds  the  rod  upon  it.  After  the  instrument  is  moved,  set 
up,  and  a  backsight  taken,  the  peg  is  pulled  up  and  carried 
in  the  pocket  until  another  turning  point  is  called  for. 
Turning  points  should  be  taken  at  about  equal  distances 
from  the  instrument  in  order  to  equalize  any  small  errors  in 
adjustment.  In  smooth  country  an  ordinary  level  will  per- 
mit of  sights  of  from  300  to  500  feet.  A  good  rodman  is  as 
necessary  to  accurate  and  rapid  leveling  as  a  good  leveler. 
A  man  who  is  inattentive  to  the  work  in  hand,  or  averse  to 
rapid  movement,  is  not  fit  for  either  place.  In  most  locali- 
ties, a  line  of  levels  of  any  considerable  length  will  have 
enough  rough  places  in  it,  i.  e.,  places  where  considerable 
changes  in  elevation  occur,  to  retard  progress,  however 
diligent  the  level  party  may  be.  Laziness  or  carelessness 
merit  immediate  discharge,  and  usually  receive  it. 

1282.  Bench  Marks. — On  railroad  surveys,  perma- 
nent points  called  bench  marks  should  be  established  at 
intervals  of  from  1,000  to  2,000  feet,  depending  upon  the 
nature  of  the  country.     Any  permanent  object,  such  as  a 

stone  door  sill,  a  tree,  or  point 
of  large  rock,  will  serve  for 
a  bench  mark.  Where  trees  are 
available,  they  are  always  used, 
the  point  being  cut  on  a  pro- 
jecting root.  On  preliminary 
lines  they  should  be  as  near  to 
the  line  as  possible.  A  tree 
with  a  large  exposed  root  is 
chosen,  the  bench  mark  is  cut 
into  the  root  in  the  form  of  a 
pyramid,  a  tack  is  driven  into  the  apex  and  the  rod  held 
upon  it.  The  tree  is  blazed  smooth  and  the  letters  B.  M., 
together  with  the  elevation  of  the  mark,  written  with  red 
chalk.  A  bench  mark  of  this  kind  is  shown  in  Fig.  202,  the 
point  being  at  A  and  the  elevation  recorded  at  />. 

1  283.  Check  Levels. — Check  levels  or  test  levels  are 
taken  for  the  purpose  of  checking  and  proving  the  accuracy 


v'W.^ 


Fig.  292. 


SURVEYING.  6G7 

of  a  line  of  levels  before  their  adoption  as  a  basis  for  con- 
struction. Usually  intermediate  points  or  stations  are  not 
taken,  but  only  the  turning  points  necessary  to  cover  the 
line.  Readings  are  taken  at  all  the  bench  marks,  and  the 
correct  elevations  marked.  The  adjustments  of  the  instru- 
ment should  be  frequently  tested,  and  the  rodman  should 
carry  a  rod  level  to  insure  the  plumbing  of  the  rod. 

1284.  "Water  Checks. — When  the  line  of  survey  fol- 
lows the  shore  of  a  body  of  water  having  no  current,  such 
as  a  lake  or  pond,  its  surface  can  be  used  as  a  check,  since 
its  level  for  any  ordinary  space  of  time  will  remain  un 
changed.  The  sea,  whose  level  is  constant,  is  the  base 
for  all  barometric  leveling,  and  at  all  seaports  for  direct 
leveling. 

1285.  Rapid  Work. — The  rate  of  progress  is  limited 
by  the  transit  party.  If  the  country  is  open  and  rolling, 
where  long  sights  are  frequent  and  chaining  easy,  the  level 
party  will  not  keep  up  with  the  transit  party.  If  the 
country  is  smooth  and  open,  both  parties  can  make  about 
the  same  progress.  If,  however,  the  country  is  thickly  cov- 
ered with  underbrush  or  heavy  timber,  the  level  party  will 
have  much  idle  time.  A  good  day's  work  will  vary,  accord- 
ing to  conditions,  from  three  to  eight  miles. 

The  target  should  be  set  by  signals  given  by  the  leveler. 
An  upward  movement  of  the  hand  is  the  signal  for  raising 
the  target,  and  a  downward  movement  the  signal  for  lower- 
ing it;  a  circle  described  by  the  hand  is  the  signal  for 
clamping  the  target,  and  a  wave  with  both  hands  indicates 
that  the  target  is  properly  set. 

All  intermediate  readings  are  read  by  the  leveler,  whose 
signal  "All  right"  is  a  single  outward  wave  of  the  hand, 
the  rodman  being  careful  to  keep  the  rod  at  full  length. 

The  rodman  should  always  call  out  the  rod  reading,  giving 
first  the  number  of  feet,  or,  if  the  reading  is  less  than  1  foot, 
call  the  figure  "  naught,"  never  "ought,"  then  pausing  a 
moment,  call  the  decimal  part  of  the  reading.  If  the  rod  is 
being  read  to  hundredths  only,  the  number,  8.40,  is  read: 


668  SURVEYING. 

eight-four,  naught;  if  8.04,  it  is  read:  eight-naught,  four. 
If  the  rod  is  to  be  read  to  thousandths,  the  number,  8.401, 
is  read:  eight-four,  naught,  one;  if  8.410,  it  is  read:  eight- 
four,  one,  naught. 

The  distinctness  of  a  call  is  in  no  way  proportional  to  the 
amount  of  noise  in  it.  A  few  days'  practice  will  enable  a 
rodman  with  moderate  effort  to  call  a  reading  so  as  to  be 
distinctly  heard  at  a  distance  of  500  feet.  Should  a  high 
wind  be  blowing,  the  sights  will  be  shorter,  owing  to  the 
vibration  of  the  instrument,  and  the  rodman's  work  propor- 
tionally lessened.  The  rod  reading  should  always  be  re- 
corded before  moving  the  instrument.  The  leveler  may 
check  the  reading  as  he  passes  the  rodman.  In  general, 
however,  the  leveler  relies  entirely  upon  the  accuracy  of  the 
rodman's  readings.  If  he  can  not  be  trusted,  his  place 
should  at  once  be  supplied  by  one  who  can  be  trusted. 

In  taking  levels  on  preliminary  railroad  surveys,  frequently 
the  turning  points,  as  well  as  intermediate  stations,  are 
read  by  the  leveler  without  being  checked  by  the  target. 
The  rodman  has  still  plenty  of  occasion  for  the  use  of  judg- 
ment, as  the  rate  of  progress  depends  largely  upon  the  care 
shown  in  the  selection  of  turning  points. 

1286.  Sources  of  Error. — The  principal  sources  of 
error  are  defects  in  adjustment,  which  are  the  fault  of  the 
leveler,  and  failure  of  the  rodman  to  plumb  the  rod,  and 
wrong  target  readings,  which  are  the  fault  of  the  latter. 
Poor  levelers  and  poor  rodmen  usually  go  in  pairs.  Haste 
or  hurry  are  poor  helps  to  progress.  One  can  do  rapid  and 
accurate  work  without  haste,  but  can  not  hurry  and  be 
either  rapid  or  accurate. 

The  sun  shining  directly  upon  the  object  glass  confuses 
the  sight.  To  prevent  this,  most  instruments  are  provided 
with  a  sun  shade,  which  fits  the  end  of  the  telescope, 
projecting  over  the  object  glass. 

If  the  sun  shade  is  lacking,  the  leveler  can  hold  his  hat  so 
as  to  shade  the  object  glass. 

Wind  is  also  a  source  of  error,  as  it  causes  the  instrument 


SURVEYING.  669 

to  vibrate,  thus  preventing  the  accurate  setting  of  the 
target.  The  leveler  should  wait  for  a  lull  in  the  wind,  dur- 
ing which,  if  his  rodman  is  alert,  he  can  get  a  close  shot. 
At  a  second  lull,  he  can  check  the  target  and  feel  safe  in 
moving  ahead. 

Individual  errors,  called  "personal  equation,"  are  defects 
in  vision  peculiar  to  the  individual,  so  that  two  persons  may- 
set  a  target  for  the  same  rod,  each  giving  a  different  read- 
ing; but  as  this  personal  equation,  or  error,  is  constant  for 
the  same  person,  it  does  not  materially  affect  the  accuracy 
of  work. 

1287.  Necessary  Degree  of  Accuracy. — In  prelim- 
inary railroad  work  an  error  of  .10  of  a  foot  per  mile  is 
allowable.  Time  spent  in  reducing  such  inaccuracies  is 
wasted.  That  painful  degree  of  accuracy  termed  "hair- 
splitting "  is  no  recommendation,  and  the  gain  in  accuracy 
is  more  than  balanced  by  increased  cost  and  loss  of  time. 
It  is  a  well-known  fact  that  small  inaccuracies  tend  to  bal- 
ance each  other,  and  that  a  line  of  levels  covering  20  miles, 
taken  with  a  self -reading  rod,  will  closely  check  a  line  taken 
with  target  readings  and  rod  level. 

1 288.  How  to  Keep  Level  Notes. — Forms  for  keep- 
ing level  notes  are  various.  One  of  the  best  forms,  rarely 
or  never  seen  in  print,  and  yet  one  which  is  in  general  use 
among  engineers,  is  shown  on  the  following  page: 

•  The  distinguishing  feature  of  this  form  of  level  notes  is  a 
single  column  for  all  rod  readings.  The  backsights  being 
additive  and  the  foresights  subtractive  readings,  they  are 
distinguished  from  other  rod  readings  by  the  characteristic 
signs  -\-  and  — .  The  turning  points,  whose  foresight  read- 
ing is  — ,  are  further  designated  by  the  abbreviation  T.  P. 

1289.  How  to  Cbeck  Level  Notes. — There  is  one 
method  of  checking  level  notes  which  is  in  universal  use.  It 
provides  for  checking  the  elevations  of  turning  points  and 
heights  of  instrument  only,  which  is  sufficient,  as  all  other 
elevations  are  deduced  from  them.  The  method  is  very 
simple    and    depends   upon    the    fact    that    all    backsights 


670 


SURVEYING. 


o 

d 

•i 

t— • 

1— t 

.£* 
*-> 

u    - 

a 
B 

4) 

c 
O 

o 
c 
u 

_c 
'C 
a. 

E 

♦J 

3 

1) 

o 

c 
_o 

♦J 

> 

o 
o 

d 
o 
I— 1 

o 

C5 

o 

CO 

CO 

C5 

o 

C5 

C5 

C5 
CO 

o 

C5 

o 
o 

o 

CO 

00 

00 

00 

C5 

o 

CO 

o 

1— t 

o 

CO 

1-5 

o 

l-H 

o 

05 

CO 

■00 

c 
M  2 

en 

o 

00 

i 

1—1 

00 

ci 
o 

l-H 

i 

3i 

1—1 

+ 

o 

o 

CO 

o 

00 

o 

1 

5< 

+ 

o 

CO 

o 

o 

1 

»o 

1— t 

+ 

O 

00 

o 

1— 1 

CO 

»o 
I— 1 

1 

1. 

Station. 

o 

T-H 

»« 

CO 

a; 

■«*< 

W3 

5 
+ 

» 

i>. 

00 

Thus,  100.00 

10.22 

5.61 

2.52 

5.41 

11.53 

11.57 

24.27 

122.59 

24.27 

SURVEYING.  071 

are  additive  or  +  quantities,  and  all  foresights  are  subtrac- 
tive  or  —  quantities.  The  level  notes  described  in  Art. 
1288  are  checked  as  follows:  The  elevation  of  the  bench 
mark  at  Station  0  is  100.00  feet,  to  which  all  backsights  or 
-j-  readings  are  to  be  added,  and  from  this  sum  all  foresights 
or  —  readings  are  to  be  subtracted.  The  sum  of  the  + 
readings  or  backsights  together  with  the  elevation  of  the 
bench  mark  at  0  is  122.59.  The  sum 
of  the  —  readings  or  foresights  is 
24.27,  and  the  difference  98.32  feet 
is  the  elevation  of  the  turning  point 
last  taken.  As  soon  as  a  page  of 
level  notes  is  filled,  the  leveler  should 
check  them,  placing  a  check  mark  -^ 
at  the  last  height  of  instrument  or 
elevation  checked.  When  the  work 
of  staking  out  or  cross-sectioning  is  being  done,  the  levels 
should  be  checked  at  each  bench  mark  on  the  line.  At  the 
close  of  each  day's  work,  the  leveler  must  check  on  the  near- 
est bench  mark. 

1290.  Profiles. — A  profile  represents  a  vertical  sec- 
tion of  the  line  of  survey.  In  it  all  abrupt  changes  in 
elevation  are  clearly  outlined.  Vertical  and  horizontal  meas- 
urements are  usually  represented  by  different  scales.  Irreg- 
ularities of  surface  are  thus  rendered  more  distinct  through 
exaggeration.  For  railroad  work  profiles  are  commonly 
made  to  the  following  scales,  viz.,  horizontal,  400  feet  = 
1  inch ;  vertical,  20  feet  =  1  inch. 

A  section  of  profile  paper  is  shown  in  Fig.  293.  Every 
fifth  horizontal  line  and  every  tenth  vertical  line  is  heavy. 
By  the  aid  of  these  heavy  lines,  distances  and  elevations  are 
quickly  and  correctly  estimated  and  the  work  of  platting 
greatly  facilitated.  The  level  notes  described  in  Art.  1288 
are  platted  in  Fig.  293.  The  elevation  of  some  horizontal 
line  is  assumed.  This  elevation  is,  of  course,  referred  to 
the  datum  line,  and  is  the  base  from  which  the  other  eleva- 
tions are  estimated.    Every  tenth  station  number  is  written 


672 


SURVEYING. 


at  the  bottom  of  the  sheet  under  the  heavy  vertical  lines. 
The  profile  is  first  platted  in  pencil  and  then  inked  in  black. 


Fig.  293. 

1291.  Grade  Lines. — The  principal  use  of  a  profile 
is  to  enable  the  engineer  to  establish  a  grade  line,  i.  e., 

a  line  showing  the  relative  proportion  of  excavation  and 
embankment  in  the  proposed  work.  The  rate  of  a  grade 
line  is  measured  by  the  vertical  rise  or  fall  in  each  hundred 
feet  of  its  length,  and  is  designated  by  the  term  per  cent. 
Thus,  a  grade  line  which  rises  or  falls  1  foot  in  each  hundred 
feet  of  its  length  is  called  an  ascending  or  descending  1  per 
cent,  grade,  and  written  +  1.0  or  —  1.0  per  hundred.  A  rise 
or  fall  of  one-half  foot  in  each  hundred  feet  is  called  a  five- 
tenths  per  cent,  grade,  and  written  +  -5  or  —  .5  per 
hundred.  The  grade  line  having  been  decided  upon,  it  is 
drawn  in  red  ink. 

Example. — The  elevation  of  Station  20  is  140.0  feet;  between  Sta- 
tions 20  and  100  there  is  an  ascending  grade  of  .75  per  cent. ;  what  is 
the  elevation  of  the  grade  at  Station  71  ? 

Solution. — To  obtain  the  elevation  of  the  grade  at  Station  71,  we 
add  to  the  elevation  of  the  grade  at  Station  20,  140  feet,  the  total  rise 
in  grade  between  Stations  20  and  71.  Accordingly,  71  —20=  51;  .75 
foot  X  51  =  38.25  feet;  140  +  38.25  =  178.25  feet,  the  elevation  of  grade 
at  Station  71. 


SURVEYING. 


673 


TOPOGRAPHICAL  SURVEYING. 
1292.  General  Deflnition. — Topographical  sur- 
veying is  the  location  and  representation  of  the  inequalities 
of  any  portion  of  the  earth's  surface.  The  portion  surveyed 
is  conceived  to  be  projected  upon  a  horizontal  plane,  called 
a  plane  of  reference,  upon  which  all  inequalities  of  sur- 
face as  well  as  all  conspicuous  objects  are  shown  in  their 
true  relative  positions.  The  simplest  and  most  generally 
used  method  of  representing  the  topography  of  a  given 
surface  is  by  means  of  contour  lines.  A  map  containing 
an  outline  of  a  given  surface,  together  with  the  contour 
lines  representing  its  inequalities,  is  called  a  contour  map 
of  that  surface. 

70^ 


Fig.  294. 

Let  A  B  C,  \n  Fig.  294,  represent  the  outline  of  a  hill,  and 
suppose  this  hill  to  be  gradually  submerged  in  water,  the 
water  rising  in  successive  heights  of  10  feet.  The  flow,  or 
shore  line,  at  each  successive  rise  is  a  contour  line.  The 
horizontal  lines  correspond  to  the  surfaces  of  the  successive 
elevations  of  the  water.  The  points  where  these  horizontal 
lines  cut  the  edge  of  the  hill  are  projected  on  the  horizontal 


074  SURVEYING. 

line  L  M.  The  irregular  lines  connecting  the  corresponding 
points  of  projection  are  contours.  In  Fig.  294  they  are 
assumed  to  be  10  feet  apart  in  vertical  measurement. 

1293.     Conduct    of   a    Topograptilcal    Survey. — 

The  manner  of  conducting  a  topographical  survey  will  de- 
pend upon  the  extent  and  outline  of  the  surface  and  the  de- 
gree of  accuracy  required.  If  the  area  be  of  comparatively 
regular  dimensions,  such  as  town  or  park  sites,  the  usual 
practice  is  to  lay  out  the  area  in  squares.  The  lines  of  di- 
vision are  the  bases  for  the  location  of  all  points  within  the 
area  whose  elevations  are  determined  by  direct  leveling. 
If  the  area  is  long  and  narrow,  as  in  a  railroad  survey,  the 
line  of  survey  is  the  base  for  the  location  of  all  points  and 
for  determining  their  elevations.  Cross-sections  of  the  sur- 
face are  taken  at  suitable  intervals,  and  changes  in  the  slope 
of  the  surface  are  measured  either  by  direct  leveling  or  with 
a  clinometer  or  slope  board. 

1  294.  The  Hand  Level. — The  usual  form,  called  the 
"Locke  level,"  from  the  name  of  the  inventor,  is  shown  in 
Fig.  295.  It  consists  of  a  brass  tube  A  B,  on  the  top  of 
which  is  a  spirit  level  C.     In  the  lower  part  of  the  tube  is  a 


mirror  which  reflects  the  point  at  which  the  bubble  should 
be  when  the  instrument  is  level.  A  small  hole  D  at  one  end 
and  a  cross-hair  at  the  other  give  the  level  line.  The  ob- 
server holds  the  level  to  one  eye,  bringing  it  to  a  level  line 
while  he  observes  the  object  to  which  the  level  is  directed 
with  the  other.  In  taking  cross-sections  with  a  Locke  level, 
the  following  rule  is  recommended:  The  topographer  has 
two  or  more  assistants,  three  is  the  better  number,  a  rod- 
man  and  two  tapemen.  The  rodman  is  provided  with  a  rod 
at  least  12  feet  in  length,  of  light  weight,  and  of  sufficient 
width  to  admit  of  large,  distinct  figures  being  painted  upon 


SURVEYING. 


675 


it,  and  divided  to  tenths  of  feet.  The  rod  is  painted  like  the 
Philadelphia  rod;  the  face  white,  tenths  of  feet  in  black,  and 
feet  in  red.  Tapemen  should  use  a  tape  100  feet  in  length, 
of  durable  material.  Chesterman  with  wire  warp  is  best. 
The  topographer  first  measures  the  distance  of  his  eye  above 
th'e  ground,  which  is  a  constant  quantity,  to  be  subtracted  from 
all  the  rod  readings.  He  then  stands  at  a  station  and  keeps 
the  rodman  at  right  angles  to  the  line  of  survey.  The  rod- 
man,  having  reached  the  end  of  a  slope,  i.  e. ,  a  point,  where 
the  rate  of  slope  changes,  he  holds  his  rod  at  the  point  and 
the  topographer  takes  the  reading  with  the  hand  level. 
From  this  reading  the  topographer  subtracts  the  constant, 
i.  e.,  the  height  of  his  eye  above  the  ground.  The  remain- 
der is  the  difference  between  the  elevation  of  the  surface 
where  the  topographer  stands  and  the  surface  where  the  rod- 
man  stands.  The  tapemen  having  measured  the  distance 
between  the  two  points,  the  rate  of  slope  is  determined  by 
dividing  the  distance  measured  by  the  difference  in  eleva- 
tion. This  method  of  taking  slopes  or  cross-sections  is 
illustrated  in  Fig.  296. 

Let  A  be  Station  156  of  a  preliminary  survey.     The  topog- 
rapher stands  at   A.      The  rodman  goes   to  the  point  B^ 


Fig.  2%. 


where  the  slope  changes,  holding  his  rod,  which  measures 
16  feet  in  length,  at  that  point.  The  topographer  sights 
with  his  hand  level  and  reads  7.5  feet  on  the  rod.  From  this 
reading  he  mentally  subtracts  5.3  ft.,  the  height  of  his  eye 


676  SURVEYING. 

above  the  ground.  The  remainder,  2.2  ft. ,  is  the  difference  in 
elevation  between  the  points  A  and  B.  Meanwhile,  the  tape- 
men  find  that  the  horizontal  distance  from  y^  to  ^  is  31  feet. 
The  rate  of  the  slope  yi  Z>'is  the  horizontal  distance  between 
the  points  A  and^,  31  ft.,  divided  by  2.2,  their  difference  in 
elevation.     The  quotient  is  14.1  and  the  slope  is  recorded 

—  -^.     The  topographer  then  moves  to  the  point  B,  and  the 

Ox. 

rodman  goes  to  C,  which  is  so  much  lower  than  B  that 
with  the  rod  held  on  the  ground  the  line  of  sight  will  pass 
over  the  top  of  the  rod.  Here  the  rodman  gives  a  "long  " 
or  "high  "  rod.  Planting  himself  firmly  at  C,  he  raises  the 
rod  until  the  line  of  sight,  from  the  topographer's  eye,  cuts 
the  top  of  the  rod,  when  the  topographer  calls  "all  right." 
He  then  notes  where  the  bottom  of  the  rod  comes,  and 
allows  it  to  slide  to  the  ground.  Then  adding  to  the  length 
of  the  rod  16  ft.,  the  distance  from  the  ground  to  the  point 
where  the  bottom  of  the  rod  came  when  the  reading  was 
taken,  he  calls  out  their  sum  to  the  topographer.  In  this 
example  the  rod  is  16  feet  and  the  addition  7  feet,  making  a 
high  rod  of  23  feet,  which  is  common  enough.  The  hori- 
zontal distance  33  feet,  as  measured  by  the  tapeman,  is  also 
called  out.  The  topographer  makes  the  subtraction  5.3 
from  23.0,  and  the  difference  17.7  is  written  as  the  numer- 
ator of  a  fraction  whose  denominator  is  the  horizontal  dis- 
tance 33.     The  slope  being  a  descending  one,  the  fraction 

17  7 
will  be — -,  a  slope  of  1  to  1.9.     In  Fig.  290,  the  slopes 

A  B  and  B  C  are  right  slopes,  i.  e. ,  on  the  right  side  of 
the  line  of  survey. 

In  taking  the  left  slopes,  the  rodman  and  topographer 
change  positions,  the  topographer  going  ahead  and  the  rod- 
man  following.  The  topographer  standing  at  D  reads  a  rod 
of  IG  feet  held  at  A.  Subtracting  the  constant  5.3,  the 
remainder  10.7  is  the  difference  between  the  elevations  of  A 
and  D  and  is  an  ascending  slope.     The  horizontal  distance 

10.7 


from  ^  to  Z>  is  30  feet  and  the  slope  is  recorded  -f- 


30 


SURVEYING. 


677 


1295.  Slope  Angles. — Slopes  are  often  measured 
with  an  instrument  called  a  clinometer,  which  measures 
the  angle  which  the  line  of  slope  makes  with  the  horizontal, 
and  is  shown  in  Fig.  297.     Tables  are  compiled  giving  the 


Fig.  297. 

angle  of  slope  and  the  horizontal  distance  for  one  foot  of  rise, 
as  follows: 

1°  is  57.3  feet  horizontal  per  1  foot  rise. 

2°  is  28.6  feet  horizontal  per  1  foot  rise. 

3°  is  19.1  feet  horizontal  per  1  foot  rise,  etc. 

1296.     Platting  Topography  in  the  Field.— While 

some  engineers  favor  the  platting  of  contour  maps  in  the 
field,  the  majority  do  not.  To  plat  the  map  in  the  field,  the 
topographer  carries  a  case,  the  cover  of  which  serves  for  a 
drawing  board.  The  line  of  survey  is  divided  into  sections 
which  are  platted  on  different  sheets,  each  sheet  containing 
some  of  the  immediately  preceding  section,  so  that  by  over- 
lapping and  pinning  them  together,  a  complete  map  of  the 
line  is  obtained.  The  topographer  carries  in  his  case  the 
sections  covering  his  day's  work,  with  the  numbers  and 
elevations  of  each  station  marked  on  the  map.  He  pins  a 
section  to  the  cover  of  the  case  with  thumb-tacks;  his 
assistants  measure  the  angle  of  the  slope  with  a  clinometer, 


678 


SURVEYING. 


together  with  the  horizontal  distance ;  and  from  the  table 
of  slopes  which  he  carries,  the  topographer  determines  the 
location  of  the  contours  and  sketches  them  on  the  map.  A 
better  practice  is  to  measure  and  record  the  slopes,  keeping 
as  close  to  the  transit  party  as  possible,  and  provide  an 
extra  man  to  work  up  the  notes  in  the  office  under  the 
direction  of  the  topographer.  • 

1297.  Eye  Measurements. — Though  practice  will 
greatly  aid  the  eye  in  estimating  distances,  yet  it  is  not 
to  be  relied  upon  when  anything  like  exactness  is  required. 
In  taking  slopes,  the  length  of  the  last  one  only  may  b'e  esti- 
mated by  the  eye.  More  distant  objects  which  lie  without 
the  possible  range  of  location  may  be  sketched  in  with  the 
aid  of  the  eye  alone. 

1298.  Form  of  Topographer's  Notes. — A  good 
form  for  a  topographer's  notes  is  shown  in  the  accompany- 
ing diagram  : 


Station. 

Lt. 

Line. 

Rt. 

Line. 

0 

^  45 

10.0 
+   30 

11.4 
35 

-1?  for  100' 

1 

for  60' 

11.5 
^  40 

11.0 
53 

7  0 

2 

for  60' 

10.3 

■^  40 

—  6 

B 

u 

a 

c 

—  4) 

o 

11.5 
50 

-II  for  100' 

3 

Same  as  2 

Same  as  2 

4 

for  50' 

11.8 
^    40 

10.5 
55 

-  ^'  for  100' 

5 

for  50' 

12.0 
■^    35 

11.3 
54 

-  '£  for  ICKV 

G 

for  60' 

10.4 
^   40 

10.5 
50 

-  y  for  100' 
4.1 

SURVEYING. 


679 


PIO.  296. 


680  SURVEYING. 

They  are  a  record  of  the  cross-sections  or  slopes  ot  a  pre- 
liminary railroad  survey,  the  line  of  which  extends  along 
the  side  of  a  steep  hill.  The  slopes  are  taken  with  a  Locke 
level  and  rod,  giving  the  actual  differences  in  elevation  be- 
tween the  points  of  change  of  slope.  The  alignment  of  the 
survey  is  shown  in  Fig.  298,  and  the  contours  are  platted 
from  the  foregoing  notes.  The  contours  are  5  feet  apart, 
i.  e.,  the  vertical  rise  between  them  is  5  feet. 

The  elevations  of  the  stations  the  topographer  has 
obtained  from  the  leveler.  The  stations  are  marked  on 
the  plat,  either  by  a  dot,  or,  what  is  better,  a  dot  enclosed 
in  a  small  circle.  The  number  of  the  station  is  marked  at 
the  right  a  little  space  ahead  of  the  circle,  the  elevation  on 
the  left  of  the  line  and  opposite  to  the  number  of  the  station. 
The  cross-section  lines  are  sometimes  drawn  on  the  map, 
very  fine  and  at  right  angles  to  the  center  line,  but  usually 
the  lines  are  omitted,  the  draftsman  giving  the  true 
direction  with  his  offset  scale  when  locating  the  contours. 
In  Fig.  298,  the  elevation  of  Station  0  is  104.6  feet.  To 
reach  the  next  contour  above,  viz.,  105,  a  rise  of  .4  foot 
must  be  made,  and  to  reach  the  next  lower  contour  a  fall  of 
4.6  feet  is  necessary.  From  the  notes,  we  find  on  the  left 
of  the  line  a  rise  of  10  feet  in  a  horizontal  distance  of  30  feet 
or  a  rise  of  1  foot  in  3  feet,  and.  for  a  rise  of  .4  foot  we  must 
go  to  the  left  of  the  line  .4x3  =  1.2  feet  to  contour  105. 
To  reach  contour  110,  which  is  5  feet  higher,  we  must  go 
5x3  —  15  feet  farther  to  the  left.  This  distance  added  to 
1.2,  the  distance  to  contour  105,  gives  16.2  feet,  the  second 
offset.  We  find  by  adding  10  feet  (the  rise  in  going  30  feet 
to  the  left  of  the  line)  to  104.6  feet,  the  elevation  of  Station 
0,  we  have  114.6  feet,  which  is  the  elevation  of  the  end  of 
the  first  slope.  An  additional  rise  of  .4  foot  must  be  made 
in  order  to  reach  contour  115.  The  second  slope  is  a  rise 
of  .8.4  feet  in  a  distance  of  45  feet,  or  a  rate  of  1  foot  in 
5.3  feet.  Multiplying  5.3  feet  by  .4,  we  have  2.1  feet,  which 
is  to  be  added  to  30  feet,  to  reach  contour  115,  and^fives  a 
distance  of  32.1  feet.  Contour  120  will  be  5.3  feet  X  5  = 
26.5  feet  beyond  contour  115,  or  58.7  feet  from  the  center  line. 


SURVEYING.  681 

In  the  same  way  the  contours  to  the  right  of  the  line  are 
located.  Tenths  of  feet  are  dropped  in  the  computed  dis- 
tances, as  they  are  too  small  for  platting,  and  the  nearest 
foot  is  taken. 

Having  located  the  contours  by  offsets  for  several  con- 
secutive stations,  points  of  equal  elevation  are  joined  free- 
hand, forming  the  contour  lines,  care  being  taken  that  lines 
of  different  elevation  are  kept  distinct  from  each  other  and 
conforming  to  the  curves  and  undulations  of  the  original 
surface. 

1 299.  Working  Up  Notes. — A  good  rule  is  to  work 
up  the  notes  for  a  considerable  section  before  platting,  thus 
avoiding  the  delay  from  continual  change  of  work.  The 
following  form  of  working  up  notes  is  a  good  one,  notes  for 
each  station  being  separated  from  those  for  other  stations 
by  a  few.  strokes  of  a  pencil.  The  example  given  is  for 
Sta.  0,  in  Fig.  298. 

Sta.  0.     Elev.  104.6. 

Rt.     14  feet  to  contour  100.  Lt.     1  foot  to  contour  105. 

Rt.     29  feet  to  contour    95.  Lt.  16  feet  to  contour  110. 

Rt.     53  feet  to  contour    90.  Lt.  32  feet  to  contour  115. 

Rt.    81  feet  to  contour    85.  Lt.  59  feet  to  contour  120. 
Rt.  110  feet  to  contour    80. 
Rt.  137  feet  to  contour    75. 

Contour  lines  are  usually  drawn  first  with  pencil  and 
afterwards  inked  in  black.  Short  gaps  are  left  in  the  lines 
at  suitable  intervals,  in  v/hich  their  elevations  are  written. 
These  should  be  of  sufficient  frequency  to  show  at  a  glance 
the  elevation  of  any  contour. 

Situations  are  continually  recurring  where  the  side  slopes 
give  but  an  inadequate  idea  of  the  topography.  This  is 
particularly  true  when  the  line  of  survey  follows  a  stream 
with  numerous  tributaries  and  where  highway  crossings  are 
frequent.  In  such  cases  the  topographer  will  supplement 
the  side  slopes  with  free-hand  sketches,  which  are  invaluable 
helps  in  making  topographical  maps. 


682  SURVEYING. 

INDIRECT  LEVELING. 

1300.  Indirect  leveling  is  the  process  of  determining 
elevations  by  either  lines  or  angles  or  both.  A  common 
example  in  indirect  leveling  is  given  in  Fig.  299. 

Let  D  B  he  a.  flag-staff  whose  height  is  required.  Set  up 
a  transit  at  A.     Level  carefully  both  the  vernier  plate  and 

ff  the    telescope.       The 

vertical  arc  will,  if  in 
adjustment,  read  at 
zero.  Sight  to  C\  the 
point  where  the  hori- 

-A     jw, (44  g^j.j^gg   ^^^    flag-staff. 

4.2'  ^  Measure   the   distance 

FIG.  299.  yi  C  =  180  feet,  CD  = 

4.2  feet,   and  the   diameter  of   the   staff  at    C=  1.5  feet. 

Measure  the  vertical  angle  C A  B  =  26°  10'.     From  rule  5, 

Art.   754,  we  have  tan  A  =    ,  ,,  ,    .    ,. z=.     One-half 

A  C  -\-  -^  dia.  staff 

diameter  staff  at  C=  .75  foot.     Substituting  known  values, 

we  have  tan  26°  10'  =  7-^77^^^,  whence  C  B—  180.75  X  tan 

180.  i  5 

26°  10'=  180.75  X.49134=  88.809  feet;  88.809  4-4.2  =  93.009 

feet  =  D  /)',  the  height  of  the  flag-staff. 

1301.  Stadia  Measurements. — The  theory  of  the 
stadia  is  familiar  to  most  engineers,  yet  comparatively  few 
of  them  make  any  practical  application  of  it,  even  when  it 
would  be  greatly  to  their  advantage. 

In  stadia  work  an  ordinary  leveling  rod  is  generally  used, 
and  answers  every  purpose.  It  should  be  made  of  hard 
wood,  such  as  mahogany,  which  is  least  affected  by  changes 
of  temperature,  and  should  be  from  10  to  12  feet  long, 
2  inches  wide,  and  about  1^  inches  thick.  It  is  divided  into 
feet,  and  each  foot  subdivided  into  tenths.  The  spaces 
corresponding  to  these  latter  divisions  are  painted  alter- 
nately red  and  white,  the  number  of  tenths  each  space 
represents  being  painted  in  prominent  black  figures  on  the 


SURVEYING.  683 

lines  of  division.  The  space  directly  below  each  footmark 
should  be  inlaid  with  a  mirror  to  reflect  the  light  and  enable 
the  surveyor  to  read  the  rod  at  long  distances  with  greater 
precision.  The  rod  should  also  be  provided  with  a  sliding 
target.  The  best  instrument  tX)  employ  in  this  class  of 
work  is  a  transit  reading  to  30".  Besides  the  horizontal  and 
vertical  cross-wires  which  appear  in  the  field  of  view  of  the 
ordinary  transit  telescope,  the  stadia  transit  is  provided 
with  two  additional  horizontal  wires  placed  parallel  with 
the  horizontal  wire  in  the  plain  transit,  and  at 

an  equal  distance  above  and  below  it,  as  shown   

in   Fig.    300.     These    two   extra  wires   are    so 

placed  that,  if  the  stadia  rod  is  held  at  a  point  

100  feet  distant  from  the  telescope,  they  will 
enclose  1  foot  of  the  length  of  the  rod.  For  ^^°-  ^^• 
example,  if  the  lower  wire  coincides  with  the  4-ft.  division, 
and  the  upper  wire  with  the  5-ft.  division  of  the  rod,  the 
distance  from  the  center  of  the  instrument  to  the  rod  will 
be  100  ft.  +  the  constant  for  the  particular  transit  used. 
The  starting  point  for  stadia  measurements  is  often  indis- 
criminately assumed  to  be  either  the  center  of  the  instru- 
ment, the  center  of  the  cross-wires,  or  from  a  plumb  line 
dropped  from  the  object  glass;  but,  owing  to  the  deflection 
of  the  sight  due  to  the  action  of  the  lenses,  the  precise 
starting  point  for  stadia  measurements  is  a  point  as  far  in 
front  of  the  object  glass  as  its  focal  length ;  for  example,  if 
the  focal  length  of  the  object  glass  is  0  inches,  the  starting 
point  is  6  inches  in  advance  of  a  plumb  line  dropped  from 
the  object  glass.  The  distance  from  this  point  to  the  centei 
of  the  instrument  is  "  constant  "  for  the  sduie  instrument, 
and  must  be  added  to  the  recorded  stadia  distance  at  every 
sight.  In  making  a  stadia  survey,  the  transit  should  first 
be  tested.  Having  found  as  level  a  plane  as  possible,  test 
and  adjust  the.  level  so  that  the  vertical  arc  will  read  zero 
when  the  telescope  is  in  a  perfectly  horizontal  position; 
measure  off  very  carefully  from  the  center  of  the  instru- 
ment, the  short  distance  equal  to  the  constant  of  the  instru- 
ment, say  1.25  feet;  from  this  point  accurately  measure  a 


684 


SURVEYING. 


distance  of  400  feet,  driving  a  stake  at  each  100  feet.  It  is 
advisable  to  measure  this  test  line  with  two  or  more  st£el 
tapes,  and  then  take  the  average.  As  it  will  be  necessary 
to  test  the  cross-wires  every  few  days,  it  is  important  that 
the  test  line  should  be  conveniently  located  and  very  accu- 
rately measured.  The  line  now  measures  401.25  feet,  as 
follows:  First  section,  measuring  from  the  center  of  the 
instrument,  101.25  feet,  then  three  sections  of  100  feet  each, 
as  shown  in  Fig.  301. 


^.25 


400' 


Direct  the  rodman  to  hold  the  rod  on  the  point  201.25  feet 
from  the  instrument,  and  adjust  the  stadia  wires  so  that 
they  will  include  2  feet  on  the  rod.  First  adjust  the  upper 
to  the  center  wire  so  as  to  include  1  foot,  then  adjust  the 
lower  to  the  center  to  include  one  foot.  When  this  has 
been  done,  let  the  rod  be  held  at  the  point  301.25  feet  distant. 
The  wires  should  now  inclose  3  feet,  1.5  feet  being  included 
between  the  upper  and  center  wires  and  1.5  feet  between 
the  center  and  lower  wires.  Now  test  the  point  at  the  ex- 
tremity of  the  line ;  the  wires  should  at  this  distance  include 
4  feet.  Instruct  the  rodman  to  hold  the  rod  o'n  the  first 
point,  101.25  feet  from  the  instrument,  and  if  the  stadia 
wires  now  include  one  foot,  the  instrument  is  in  adjust- 
ment; if  not,  the  operations  must  be  repeated  until  the 
instrument^ reads  correctly  at  every  point.  The  ratio  of  the 
constant  does  not  increase  with  the  distance,  but  remains 
the  same  whether  the  distance  of  the  sight  be  50  or  2,500 
feet. 

At  the  .beginning  of  a  survey,  the  target  on  the  rod  is  set 
at  a  height  equal  to  that  of  the  instrument,  i.  e.,  the  dis- 
tance from  the  ground-line  to  the  axis  of  the  telescope. 
This  is  done  with  the  view  of  having  the  line  of  sight  par- 
allel with  an  imaginary  line  between  the  foot  of  the  instru- 


SURVEYING. 


685 


ment  and  the  foot  of  the  rod,  which  gives  the  exact  vertical 
angle  or  degree  of  slope  between  the  instrument  and  rod 
and  a  perfectly  level  plane.  The  rod  is  now  held  on  a  point 
where  a  sight  is  desired,  and  the  transitman  turns  the  tele- 
scope until  the  center  wire  and  the  center  line  of  the  target 
coincide;  see  Fig.  302.  He  then  clamps  the  telescope,  and 
reads  the  angle  of  elevation  or  depression,  as  the  case  may 
be,  on  the  vertical  arc^  which  is  say  10°  26' ;  and,  if  the  rod 
is  held  on  a  point  at  a  greater  elevation  than  that  of  the 
telescope,  this  angle  will  be  one  of  elevation,  and  he  will 
record  it  thus,  +  10°  26';  but  if  the  rod  is  held  on  a  point 
lower  than  the  instrument,  the  telescope  will  be  correspond- 
ingly depressed,  and  the  angle  is  recorded  thus,  —  10°  26'. 
The  distance  on  the  rod  intercepted  by  the  stadia  wires  is 


Fig.  302. 


read  and  recorded.  Assuming  that  the  lower  wire  coincides 
with  the  3.5  ft.  division  line,  and  the  upper  one  cuts  the  rod 
at  7.46  feet,  the  intercepted  distance  is  7.46  —  3.5  =  3.96 
feet,  and  is  thus  recorded.  The  needle  is  next  read,  or,  if  it 
be  an  angular  survey,  the  direction  is  platted  and  recorded. 
Having  thus  obtained  the  vertical  angle,  intercepted  dis- 
tance, and  bearing,  this  sight  is  finished  and  the  surveyor  is 
ready  to  move  to  the  next  station. 

Before  any  platting  can  be  done,  the  distances  must  be 
calculated  and  reduced  to  the  horizontal.  This  may  be  ac- 
complished by  means  of  the  table  of  Horizontal  Distances 
and  Differences  of  Elevation  for  Stadia  Measurements.  In 
using  the  tables,  proceed  as  follows:  Look  for  the  vertical 
angle,  in  this  instance  10°  26',  and  under  the  head  Hor.  Dist. 
find  the  number  96.72.     Then,  this  number  multiplied  by 


686  SURVEYING. 

the  distance  intercepted  by  the  stadia  wires,  viz.,  3.96, 
equals  96.72  X  3.96  =  383.01;  now,  at  the  foot  of  the  page, 
under  10°  and  opposite  c  =  1.25  (the  constant  of  the  instru- 
rnent),  find  the  corrected  distance  1.23,  which,  added  to 
383.01,  gives  384.24:  feet,  the  corrected  horizontal  distance, 
which  is  recorded  in  the  column  provided  for  that  purpose 
in  the  note  book. 

The  difference  of  level  is  found  thus  :  Under  the  head 
Diff.  Elev.,  find  17.81,  the  number  corresponding  to  the 
vertical  angle  10°  26'.  This  number  multiplied  by  the  in- 
tercepted distance  equals  17.81  X  3.96  =  70.53;  at  the  foot 
of  the  column  find  .23,  which,  added  to  70.53,  gives  70.76 
feet  as  the  difference  of  elevation,  and  is  recorded  as  such 
in  its  proper  place.  Proceed  in  the  same  manner  to  find 
the  horizontal  distances  and  differences  of  level  of  all  the 
other  points  observed.  The  relative  elevations  of  the  vari- 
ous points  observed,  above  or  below  any  adopted  datum  line 
or  plane  of  reference,  can  be  readily  determined  by  means 
of  the  signs  +  and  —  prefixed  to  each  vertical  angle  recorded. 
Thus,  assuming  the  survey  to  start  from  a  B.  M.  497.32  feet 
above  the  adopted  plane  of  reference,  and  the  first  angle  re- 
corded to  be,  as  before  stated,  +  10°  26',  corresponding  to  a 
difference  of  level  of  +  70.76  feet,  the  point  observed  will  be 
497. 32  +  70. 76  =  568. 08  feet  above  th3  datum  plane.  Where, 
however,  boundary  lines  only  are  being  run,  it  is  unneces- 
sary to  compute  the  levels,  but  the  vertical  angles  must  be 
recorded  in  all  cases,  in  order  to  correct  the  distances. 

The  calculations  may  be  made,  without  the  use  of  tables, 
in  the  following  manner: 

To  obtain  the  horizontal  distance,  the  following  formula 
is  employed : 

D—c  cos  n  -\-a  k  cos'  «,  (94.) 

in  which  D  =  the  corrected  distance ;  c  =  the  constant ;  a  k  = 
the  stadia  distance,  and  ;/  =  the  vertical  angle. 

Assume,  as  before,  a  vertical  angle  of  +  10°  26'  and  an 
intercepted  distance  of  3.96  feet.  As  each  foot  of  the  rod 
intercepted  by  the  stadia  wires  corresponds  to  a  distance  of 


SURVEYING. 


687 


100  feet,  an  interception  of  3.90  feet  corresponds  to  a  dis- 
tance of  396  feet,  called  herein  the  stadia  distance,  i.  e.,  the 
distance   from  the  rod  to  the  point  outside  the    telescope 
where  the  stadia  measurement  begins. 
Applying  the  formula,  we  have, 

D  =  1.25  cos  10°  20'  +  396  cos'  10°  26'  = 
125  X  .  98347  +  390  X  .  98347'  =  384. 24  ft. 

To  obtain  the  difference  of  level  E,   apply  the  following 
formula: 

.  ,  sin  2  «  /rk-  \ 

Applying  this  formula  to  the  preceding  example,  we  have 
E  -  1.25  X  .18109  +  396  X  .17810  =  70.75,    since    2  «  = 


10°  26'  X  2  =  20°  52'  and 


sin  20°  52'       .35619 
2 


=  .17810. 


SURVEY   OF  BEAVER  CREEK. 


c 

c" 
_o 
'■3 

OJ 

5 

4-> 

cn 

5 

O 

o 

Bearing. 

Vert. 
Angle. 

S  1 

t  I 
21  o 

0 

1 

396 

384 

N    1°  15  W 

+  10°  26' 

+  70.71 

1142.21 

A 

201 

Due  E 

+  20°  11' 

B 

404 

S  80°  10  W 

-  11°  14' 

C 

187 

S  76°  20  W 

-  14°  22' 

D 

563 

S  68°  32  W 

+    3°  12' 

2 

384 

N  20°  15  W 

-    0°  16' 

The  tables  of  Horizontal  Distances  and  Differences  of 
Elevation  for  Stadia  Measurements  are  computed  for 
observations  taken  on  a  vertical  rod  held  perfectly  plumb. 

Fig.  303  shows  the  method  of  keeping  sketch  and  notes  in 
topographical  work. 


688 


SURVEYING. 


1302.     An  efflcient   topoy^raphical  survey  is  one 

which  fully  serves  every  purpose  for  which  it  is  made.  Its 
value  depends  more  upon  the  accuracy  of  that  which  is 
represented  rather  than  the  minuteness  or  quantity  of 
detail.  The  topographer  should  be  able  to  readily  and  m- 
telligently  decide  between  what  is  important  and  what  is 
not    important,    and    invest    his    time    and    labor   accord- 


FlG.  303. 

ingly,  taking  nothing  for  granted  and  never  indulging  in 
guesswork. 

1303.  The  Aneroid  Barometer. — Fig.  304  shows 
an  aneroid  barometer,  a  substitute  for  the  mercurial  barom- 
eter, which  latter  is  not  readily  portable.  It  consists  of  a 
box  of  thin  corrugated  copper,  exhausted  of  air.  An  in- 
crease in  the  weight  of  the  atmosphere  compresses  the  box, 
and  a  reduction  in  weight  admits  of  the  box  being  expanded 
by  a  spring  inside.  This  spring  is  connected,  by  a  system  of 
levers,  with  a  dial  which  indicates  the  pressure  of  the 
atmosphere.  The  face  is  graduated  to  correspond  with  the 
heights  of  the  mercurial  barometer.     A  thermometer  is  also 


SURVEYING. 


689 


attached  to  the  face  and  shows  the  temperature  when  the 
readings  are  taken. 


Fio.  :J04. 
1304.  How  to  Determine  Difference  in  Eleva- 
tions With  tlie  Aneroid  Barometer. — The  formula 
given  is  that  used  by  the  Engineer  Corps  of  the  United 
States  Army.  The  aneroid  barometers  used  are  adjusted 
to  agree  with  the  mercurial  barometer  at  a  temperature  of 
32°  Fahrenheit  at  the  sea  level  in  latitude  45°.  Observa- 
tions at  the  two  stations  whose  difference  in  elevation  is 
required  should  be  made  as  nearly  simultaneous  as  possible, 
as  temperature  and  atmospheric  conditions  are  constantly 
changing. 

Let  Z  —  difference  of    elevation  of   the  two  stations  in 
feet; 
//  =  the  reading  in  inches  of  the  barometer  at  the 
lower  station; 


690  SURVEYING. 

//"=  the  reading  in  inches  of  the  barometer  at  the 
higher  station; 
/  and /'  =  temperature  (Fahr.)  of  the  air  at  the  two  sta- 
tions. 
Then, 

Z=  (log//-  log /^)  X  G0,384.3  X  (l  +^^^^=^).     (96.) 

Example. — Reading  at   lower  station,    /;  =  29.52  in.,    /  =  70°;   at 
higher  station,  H  =  27.15  in.,  /'  =  62°. 

Log  of /4,    29.52=1.47012 
Logoff/,  27.15  =  1.43377 

Difference  =    .03635 
/  +  /'-64      .  ^  70+62-64      ,  .„„ 
^+       900        =^^ 900 =  10'55- 

Hence,  Z=  .03635  x  60,384.3  x  1.0755  =  2.360.4  feet,  the  diflference 

between  the  elevations  of  the  two  stations. 

Tables  are  prepared  giving  values  of  (log  //  —  log  H)  X  60,384.3  and 

t  ■\- 1'  —  64' 
of  1  4 jjjr-r ,  which  greatly  simplifies  the  work  of  determining 

differences  of  elevations. 


HYDROGRAPHIC    SURVEYING. 

1305.  Hydrographic  surveying  is  the  process  of 
determining,  by  means  of  soundings,  the  location  of  the  deep 
and  shallow  places  of  harbors,  sounds,  rivers,  etc.,  and 
recording  them  in  charts  for  the  use  of  engineers  and 
navigators. 

1306.  Sounding. — Sounding  is  measuring  the  depth 
of  water.  The  surface  of  the  water  forms  the  datum  line, 
and  the  various  depths  measure  the  undulations  or  changes 
of  elevation  of  the  bottom  of  the  body  of  water  being 
sounded.  The  extent  of  knowledge  of  the  bottom  gained 
will  depend  upon  the  number  and  accuracy  of  the  soundings. 

For  depths  to  18  feet,  a  sounding  rod  graduated  to  feet 
and  tenths  is  used ;  for  greater  depths,  a  lead  line,  marked 
to  fathoms  and  half  fathoms,  is  employed.  It  will  be  found 
necessary  to  keep  the  lead  line  well  stretched  and  its  length 
frequently  tested. 


SURVEYING. 


691 


1307.  Conduct  of  Survey. — The  mode  of  conduct- 
ing a  hydrographic  survey  is  as  follows:  Stations  at  con- 
spicuous points  on  shore  are  first  carefully  located  by 
trigonometrical  surveying.  They  form  the  base  line  by 
which  all  irregularities  of  shore  line  and  the  location  of  all 
soundings  are  determined.  A  good  station  mark  is  a  post 
set  firmly  in  the  ground  with  about  one  foot  of  its  length 
exposed.  A  hole  is  bored  in  the  center  of  the  top  of  the 
post  and  a  flagpole  set  in  it.  The  pole  can  be  pulled  out 
and  a  transit  set  directly  "over  the  station.  Each  station 
should  be  distinguished  by  the  combination  of  colors  on  the 
flag,  and  the  number  of  the  station  should  be  distinctly 
marked  on  the  post.  A  permanent  bench  mark  must  be 
established  and  the  height  of  water  at  the  time  of  the 
soundings  recorded. 

Buoys  are  made  of  light  wood,  and  painted  in  such  colors 
as  will  make  them  conspicuous. 


Fig.  305. 

The  location  of  buoys  and  soundings  is  illustrated  in  Fig. 
.'>05.  The  stations  A  and  B  are  located  and  their  distance 
apart  known.  A  transit  is  set  up  at  each  station  and  back- 
sighted  to  a  rod  at  the  other;  the  vernier  plate  is  then  un- 
damped and  the  leadsman  in  the  boat  is  carefully  followed 
with  the  instrument.  At  a  given  signal,  the  leadsman  takes 
a  sounding,  and  both  instruments  sight  to  him  and  read  the 
angles,  which  give  a  side  and  two  adjacent  angles  of  a 
triangle  from  which  to  determine  the  location  of  the  point  D. 
In  the  same  manner  C  and  any  number  of  points  can  be 
located.  A  man  in  the  boat  records  the  time  and  the  sound- 
ings as  they  are  read  by  the  leadsman. 


692  SURVEYING. 

1308.  Tide  Gauges. — By  means  of  a  tide  gauge  the 
height  of  water  at  any  time  may  be  known.  The  datum  or 
zero  line  is  mean  low  spring  tide.  A  simple  form  of  tide 
gauge  is  a  board  nailed  to  the  upright  front  of  a  dock.  The 
face  should  be  painted  white  and  graduated  to  half-feet  or  to 
feet  and  tenths,  and  the  zero  line  set  at  mean  low  spring  tide. 
The  feet  marks  should  be  in  heavy  black  figures,  so  that 
they  may  be  easily  read. 

The  tide  gauges  used  by  the  government  are  automatic, 
and  are  provided  with  an  indicator  which  registers  on  paper 
the  fluctuations  of  the  tide. 


LAND  SURVEYING. 


1  309.  The  United  States  System  of  Surveying 
Public  Lands. — The  public  lands  of  the  United  States  are 
divided  and  laid  out  into  approximately  equal  squares,  the 
sides  of  which  are  true  north  and  south  or  east  and  west 
lines.  This  is  effected  by  means  of  meridian  lines  and 
parallels  of  latitude  established  six  miles  apart.  The  squares 
thus  formed  are  called  to^wnships,  and  contain  36  square 
miles  or  sections.  Each  section  contains,  as  nearly  as  may 
be,  640  acres,  giving  an  approximate  area  of  23,040  acres  for 
each  township. 

1310.  Principal  Meridians. — A  principal  merid- 
ian running  due  north  and  south  and  a  base  line  running 
due  east  and  west  are  established  astronomically,  and  the 
half-mile,  mile,  and  six-mile  corners  are  permanently  marked 
on  them.  These  two  lines  form  the  basis  of  all  subsequent 
divisions  into  townships  and  sections.  All  other  lines,  with 
the  exception  of  these  two  and  the  standard  parallels,  are 
run  with  the  compass  and  chain. 

Fig.  306  represents  a  section  of  country  thus  laid  out.  The 
scale  is  10  miles  to  1  inch  =  633600  :  1.  The  diagram  shows 
the  principal  meridian  running  truly  north  and  south,  and 
a  base  line  which  is  a  parallel  of  latitude  running  truly 
east  and  west.  Parallel  to  these  are  other  lines  6  miles  apart, 
forming  townships.  All  the  townships  situated  north  or 
south  of  each  other  form  a  range,  the  ranges  being  named 
by  their  number  east  or  west  of  the  principal  meridian. 
The  seven  ranges  east  and  seven  west  of  the  principal  merid- 
ian, shown  in  Fig.  306,  are  described  as  R.  1  E,  R.  1 W,  etc. 
The  townships  in  each  range  are  designated  by  their  num- 
ber north  or  south  of  the  base  line.     Thus,  in  the  diagram. 


G94 


LAND   SURVEYING. 


the  township  marked  A  is  denoted  by  T.  3  N,  R.  4  W;  that 
marked  B,  by  T.  2  S,  R.   3  E.     These  abbreviations  should 

l^Stknd^rd  Parallel  Noi^th. 


Base 


,!S 


Line. 


It 


1^^  Standard  Parallel  ^outh. 


Fig.  306. 

be  read  townsJiip  3  north,   range  J^  ivest,    and  toxvnship  2 
south,  range  3  east. 

1311.     To-v^'nslilp  Divisions. — Each  township  is  divi- 
ded into  36  sections,   each  one  mile  square  and  containing 

640   acres   as    nearly   as 

TV 

^  maybe.     The  sections  in 

each  township  are  num 
bered  from  1  to  36,  as 
shown  in  Fig.  307.  The 
numbering  of  the  sec- 
tions begins  at  the  north- 
east corner  of  the  town- 
ship and  goes  west  from 
1  to  6,  then  east  from  7 
to  12,  and  so  on  alter- 
nately until  section  30  in 
the  southeast  angle  of 
the  township  is  reached. 
The  sections  are  sub- 
divided  into  quarter-sections,  each  half  a  mile  square  and 


W 


6 

5 

4 

3 

2 

1 

7 

8 

9 

10 

11 

12 

18 

n 

16 

15 

14 

13 

19 

20 

21 

22 

23 

24 

30 

29 

28 

27 

26 

25 

31 

32 

33 

34 

35 

3e 

E 


S 

Fig.  307. 


LAND    SURVEYING.  695 

containing  IGO  acres,  and  sometimes  into  half  quarter-sections 
of  80  acres  and  quarter  quarter-sections  of  40  acres.  By  this 
system  the  smallest  subdivision  of  land  can  be  accurately 
located ;  as,  for  example,  the  southeast  quarter  of  section  36 
in  township  one  south  in  range  two  west  of  Willamette 
meridian. 

1312.  Obstacles. — The  law  requires  that  the  lines  of 
the  public  surveys  shall  be  governed  by  the  true  meridian, 
and  that  the  townships  shall  be  six  miles  square,  two  condi- 
tions involving  a  mathematical  impossibility,  for  strictly 
conforming  to  the  meridian  would  necessarily  throw  the 
township  out  of  square,  for  the  reason  that  a  degree  of  longi- 
tude, which,  at  the  equator,  is  69^  miles,  constantly  dimin- 
ishes as  one  approaches  the  poles.  As  the  meridian  lines  are 
strictly  adhered  to,  the  requirements  of  the  law  respecting 
areas  are  not  fulfilled.  The  townships  assume  a  trapezoidal 
form  which  increases  the  higher  the  latitude  of  the  surveys. 
To  meet  these  conditions  the  law  provides  that  the  sections 
shall  contain  G40  acres,  as  nearly  as  may  be,  and  further  pro- 
vides that  "  in  all  cases  where  the  exterior  lines  of  the  town- 
ship thus  to  be  subdivided  into  sections  and  half-sections 
shall  exceed  or  shall  not  exceed  six  miles,  the  excess  or 
deficiency  shall  be  specially  noted  and  added  or  deducted 
from  the  western  or  northern  ranges  of  sections  or  half- 
sections  in  such  township,  according  as  the  error  may  be  in 
running  the  lines  from  east  to  west  or  from  south  to  north." 
In  order  to  throw  the  excesses  or  deficiencies,  as  the  case 
may  be,  on  the«^r///and  tcr.?/ sides  of  a  township,  according 
to  law,  it  is  necessary  to  survey  the  section  lines  from  south 
to  north  on  a  true  meridian,  leaving  the  result  in  the  northern 
line  of  the  township  to  be  governed  by  the  convexity  of  the 
earth  and  the  convergency  of  meridians. 

Thus,  suppose  the  land  to  be  surveyed  lies  between 
46°  and  47°  of  north  latitude.  The  length  of  a  degree  of 
longitude  in  latitude  46°  north  is  taken  as  48.0705  statute 
miles,  and  in  latitude  47°  north  as  47.1944  miles.  The  dif- 
ference, or  convergency  per  square  degree,  =  .8761  mile  = 


696  LAND    SURVEYING. 

70.08  chains.  The  convergency  per  range  (8  per  degree  of 
longitude)  equals  one-eighth  of  this  distance  or  8. 76  chains, 
and  per  township  (11^  per  degree  of  latitude)  will  equal 
8.76  chains  divided  by  11^=. 76  chain.  Hence,  we  know 
that  the  width  of  townships  along  their  northern  boundary  is 
76  links  less  than  on  their  southern  boundary.  The  town- 
ships north  of  the  base  line,  therefore,  become  narrower  and, 
narrower  than  the  six-mile  width  with  which  they  start  by 
that  amount. 

1313.  Standard  Parallels.  —  Standard  parallels, 
called  correction  lines,  are  established  at  intervals  of 
30  miles  to  provide  for  the  correction  of  the  error  arising 
from  the  convergency  of  the  meridians.  They  also  serve  to 
limit  errors  resulting  from  inacciiracies  in  measurement. 
Such  correction  lines  .when  lying  north  of  the  principal  base 
line  form  new  base  lines  for  the  surveys  north  of  them. 
The  convergency  or  divergency  is  taken  upon  these  correc- 
tion lines,  from  which,  as  base  lines,  the  townships  start 
again  with  their  proper  widths.  On  these  correction  lines, 
therefore,  double  corners  will  be  found,  one  set  being  the 
closing  corners  of  the  surveys  ending  there,  and  the  other  set 
the  standard  corners  of  the  surveys  starting  there. 

1314.  Running    Township   Lines. — The   principal 

meridian,  the  base  line,  and  the  standard  parallels  having 
been  first  astronomically  run,  measured,  and  marked  accord- 
ing to  instructions  on  true  meridians  and  true  parallels  of 
latitude,  the  process  of  running,  measuring,  and  marking 
the  exterior  lines  of  townships  is  as  follows: 

For  townships  north  of  the  base  line  and  west  of  the 
principal  meridian,  commence  at  Station  No.  /  (Fig-  308), 
the  southwest  corner  of  T.  1  N,  R.  I  W,  as  established  on 
the  base  line,  thence  run  north  on  a  true  meridian  line 
480  chains,  establishing  the  half-mile  and  mile  corners  there- 
upon, according  to  instructions,  to  No.  2,  which  is  the  north- 
west corner  of  the  same  township.  There  establish  the 
corner  of  townships  1  and  l  N,  ranges  1  and  2  W;  thence 
run  east  on  a  random  or  trial  line,  setting  temporary  stakes 


LAND    SURVEYING. 


697 


at  the  half-mile  and  mile  points  and  noting  the  distance 
where  the  line  intersects  the  eastern  boundary  north  or 
south  of  the  true  or  established  corner.  Run  and  measure 
westward  on  the  true  line,  establishing  permanent  half-mile 
and  mile  corners,  noting  all  water  crossings  and  the  charac- 
ter of  the  land,  as  per  instructions,  to  No.  If.,  which  is  iden- 
tical  with   No.    2.     The  last   half-mile   will    fall   short  of 


Standard 

Parallel. 

28 

14 

14 

28 

27 

13 

13 

27 

25     26 

11 

12 

12 

11 

26 

25 

24 

10 

10 

24 

, 

22     23 

8 

9 

9 

8 

23 

22 

21 

7 

7 

21 

19     20 

5 

6 

6 

5 

20 

19 

18 

4 

4 

18 

16      17 

2 

3 

3 

2 

17 

16 

29 

15 

1 

1 

15 

Base 

e 

Li 

ne 

-  . 

Pig.  808. 

40  chains  by  about  the  amount  of  the  calculated  conver- 
gency  per  township,  which,  in  the  above  supposed  case, 
equals  76  links. 

The  terms  random  and  true  lines  are  explained  in  Fig. 
309.  The  boundary  from  Station  1  to  Station  ^  is  a  true 
meridian  and  480  chains  in  length,  with  permanent  corners 
set  at  each  half-mile  and  mile.     From  A  run  and  measure 


698 


LAND    SURVEYING. 


towards  ^  on  a  true  east  and  west  line,  as  shown  by  ide  dot- 
ted line  A  B,  which  is  called  a  random  line,  setting  tem- 
porary half-mile  and  mile  posts.  This  random  or  trial  line 
being  run  on  a  parallel  of  latitude,  must  intersect  the  prin- 
cipal meridian  near  the  true  corner  C,  previously  established. 
The  return  or  true  line  always  connects  this  true  corner 
with  the  one  from  which  the  random  starts.     Random  lines 


Random  Line  479JSS  chains"  47925  links. 

>*^    '>A,^19^^0^40     40     40     40      40    40     40     40      40  39.23 

'^^^^^^^^^^^^"io-lo-io-Jo-io-jo^ 
True  Line. 


Sta.l 


40 


T.l.N.Rl.W. 


S 


Base   Line. 


5\ 


•it 


Fig.  309. 


are  either  true  east  and  west  or  true  north  and  south  lines, 
i.  e.,  they  are  either  parallels  of  latitude  or  true  meridians. 
Suppose  the  random  line  intersects  the  principal  meridian 
X  Fat  i?,  75  links  to  the  north  of  the  true  or  established 
corner  at  C\  the  length  of  A  B  is  479  chains  and  25  links. 
The  triangle  A  B  C  is  a  right-angled  triangle,  right  angled 
at  B',  dividing  B  C=75  links  by  A  ^=47925  links,  we 
have  the  tangent  of  the  angle  BA  C=  j^Wr  =  .00156  = 


LAND    SURVEYING.  699 

tan  0°  05'.  The  angle  B  C  A  is,  therefore,  90°  =  0°  05'  = 
89°  55',  and  the  return  course,  or  true  line,  C  A  is 
N  89°  55'  W.  Setting  the  instrument  over  the  true  or  estab- 
lished corner  C,  the  compass  is  set  for  the  true  course  C  A, 
N  89°  55'  W,  and  measuring  40  chains  from  C,  a  permanent 
half-mile  or  quarter-section  post  is  set,  40  chains  further  a 
mile  or  section  post  is  set,  and  so  on,  setting  half-mile  and 
mile  posts  at  regular  intervals  of  40  chains  until  the  last 
half-mile  post  is  set;  between  it  and  the  township  corner  A, 
the  distance  is  but  39  chains  and  25  links,  thus  leaving 
the  deficiency  in  the  western  tier  of  sections  as  prescribed 
by  law. 

In  case  the  random  line  materially  falls  short,  or  overruns 
in  measurement,  or  intersects  the  eastern  boundary  at  a  con- 
siderable distance  from  the  established  corner,  it  will  be  evi- 
dent that  there  has  been  considerable  error  either  in  direction 
or  measurement  of  the  lines,  or  both,  and  the  lines  must  be 
retraced  even  if  it  should  be  found  necessary  to  rerun  the 
meridianal  boundaries  of  the  township  (especially  the  west- 
ern boundary)  so  as  to  discover  and  correct  the  error.  The 
true  corners  must  be  established,  and  the  false  ones  destroyed 
and  obliterated,  and  all  facts  carefully  set  forth  in  the  notes 
so  as  to  avoid  future  confusion. 

Then  proceed  north  from  4  to  5,  establishing  corners  as 
before;  No.  5  is  the  N  W  corner  of  T.  2  N,  R.  1  W;  east 
to  No.  6  (the  N  E  corner  of  the  same  township),  west 
to  No.  7  (the  same  as  No.  5),  north  to  No.  8  (the  N  W  cor- 
ner of  T.  3  N,  R.  1  W),  east  to  No.  9  (the  N  E  corner  of 
the  same  township),  west  to  No.  10  (same  as  No.  8),  north 
to  No.  11  (the  N  W  corner  of  T.  4  N,  R.  1  W),  east  to 
No.  12  (the  N  E  corner  of  the  same  township),  west  to 
No.  IS  (same  as  No.  ll),  and  thence  north  on  a  true  merid- 
ian to  the  standard  parallel  or  correction  line  (which  is  here 
five  townships,  or  30  miles,  north  of  the  base  line),  throwing 
the  difference  over  or  under  four  hundred  and  eighty 
chains  on  the  last  half  mile,  according  to  law.  At  the  inter- 
section with  the  standard  parallel  establish  the  closing  corner, 
the  distance  of  which  from  the  standard  corner   must  be 


700  LAND    SURVEYING. 

measured  and  noted  as  required  by  the  instructions.  In 
case  any  obstruction  should  have  prevented  the  extension  of 
the  standard  parallel  along  the  field  of  the  present  survey, 
the  surveyor  will  establish  a  corner  for  the  township,  subject 
to  correction,  should  the  parallel  be  extended.  The  surveyor 
then  returns  to  the  base  line,  and,  from  the  southwest  corner 
of  T.  1  N,  R.  2  W,  carries  up  another  tier  of  townships, 
closing  as  before. 

For  townships  north  of  the  base  line  and  east  of  the  prin- 
cipal meridian  the  order  of  survey  is  as  follows:  Beginning 
at  the  southeast  corner  of  T.  1  N,  R.  1  E,  proceed  as  with 
townships  north  and  ivest,  except  that  the  trial  or  random 
line  is  run  and  measured  west  and  the  true  line  east,  throw- 
ing the  difference  over  or  under  480  chains  on  the  west  end 
of  the  line.  Accordingly,  the  surveyor,  having  measured  his 
trial  line  west,  will  first  determine  the  length  of  the  last  half- 
section  line,  and  commence  the  measurement  of  the  true  line 
with  such  excess  or  deficiency,  and,  consequently,  the  re- 
maining measurements  will  all  be  exact  half  miles  and 
miles. 

1315.  Running  Section  Lines. — The  interior  or 
sectional  lines  of  all  townships,  however  situated  with  refer- 
ence to  base  and  meridian  lines,  are  laid  off  and  surveyed, 
as  shown  in  Fig.  310. 

In  this  figure  the  squares  and  large  figures  represent  sec- 
tions; the  small  figures  are  referred  to  in  the  following  di- 
rections. Commence  at  No.  1  (see  small  figure  in  the 
diagram)  which  is  a  township  boundary  for  sections  1,  2,  SS, 
and  36;  thence  run  north  on  a  true  meridian;  at  40  chains 
establish  a  half-mile  or  quarter-section  post,  and  at  80  chains 
establish  the  corner  of  sections  25,  26,  35,  and  36.  Thence 
east  on  a  random  line  to  No.  S,  setting  a  temporary  quarter- 
section  post  at  40  chains,  noting  the  measurement  to  No.  3 
and  the  distance  of  the  random's  intersection  north  or  south 
of  the  true  or  established  corner  of  sections  25,  S6^  30,  and 
31.  Thence  correct  west  on  a  true  line  to  No.  4,  setting  the 
quarter-section  post  on  this  line  equidistant  from  the  two 


LAND    SURVEYING. 


701 


corners  whose  distance  apart  is  now  known.  In  like  manner 
proceed  from  J(.to  5,  5  to  6,  6  to  7,  and  so  on  to  No.  16,  the 
corner  of  sections  i,  2,  11,  and  12,  thence  north  on  a  random 
line  to  No.  17,  setting  a  temporary  quarter-section  post  at 
40  chains  and  noting  the  length  of  the  whole  line  and  the 
distance  of  the  random's  intersection  east  or  west  of  the  true 
corner  of  sections  1,  2,  33,  and  36  established  on  the  town- 
ship boundary,  then  southwardly  from  the  latter  on  a  true 


31 

32 

33 

34 

35 

36 

97 

71 

53 

35 

17 

1 

0 

5 

4 

3 

2 

1 

99       98 

96       72 

70       54 

52      36 

34      18 

16 

94      95 

68       69 

50      51 

32      33 

14       15 

12 

7 

8 

9 

10 

11 

12 

92 

91 

67 

49 

31 

13 

93 

89       90 

65       66 

47      48 

29      30 

11       12 

13 

18 

17 

16 

15 

14 

13 

87 

86 

64 

46 

28 

10 

88 

84      85 

62       63 

44     45 

26      27 

8         9 

24 

19 

20 

21 

22 

23 

24 

82 

81 

61 

43 

25 

7 

83 

79       80 

59      60 

41      42 

23      24 

5         6 

25 

30 

29 

28 

27 

26 

25 

7T 

76 

58 

40 

22 

4 

'    78 

74       75 

56       57 

38       39 

20      21 

2        3 

36 

31 

32 

33 

34 

35 

36 

73 

55 

37 

19 

1 

6 


18 


19 


30 


31 


6 


4  3 

Fig.  310. 


line,  noting  the  course  and  distance  to  No.  16,  the  established 
corner  to  sections  1,  2,  11,  and  12,  care  being  taken  to  estab- 
lish the  quarter-section  post  at  40  chains  from  said  section 
corner,  thus  throwing  the  excess  or  deficiency  on  the  north- 
ern half  mile,  according  to  law.  Proceed  in  like  manner 
through  all  the  intervening  tiers  of  sections  to  No.  13,  the 
corner  of  sections  31,  32,  5,  and  6.  Thence  north  on  a  true 
meridian  80  chains  to  7^  setting  a  quarter-section  post  at 


702  LAND   SURVEYING. 

40  chains,  and  at  80  chains  setting  corner  of  sections  29,  30, 
31,  and  32;  then  east  on  a  random  to  75,  setting  temporary 
quarter-section  post  at  40  chains,  noting  the  entire  measure- 
ment to  the  eastern  boundary  and  the  distance  of  the  ran- 
dom's intersection  north  or  south  of  the  true  corner  of  sec- 
tions 28,  29,  32,  and  33;  thence  west  on  a  true  line,  setting 
the  quarter-section  post  on  the  true  line  and  equidistant 
from  either  end,  to  No.  76,  which  is  identical  with  74;  thence 
west  on  a  random  line  to  77,  setting  temporary  quarter-sec- 
tion post  at  40  chains,  noting  the  full  measurement  of  the 
line  and  the  distance  of  the  random's  intersection  with  the 
township  boundary  nortJi  or  sontli  of  the  established  corner 
of  sections  30,  31,  25,  and  3Q;  thence  eastwardly  on  the  true 
line,  giving  its  course  and  setting  the  quarter-section  post 
40  chains  from  the  corner  of  sections  29,  30,  31,  and  32,  thus 
throwing  the  excess  or  deficiency  of  measurement  on  the 
western  half  mile  of  the  section  according  to  law.  Proceed 
ftorth  in  like  manner  from  No.  78  to  79,  79  to  80,  80  to  81, 
and  so  on  to  No.  9J^,  the  southeast  corner  of  section  6,  where, 
having  established  the  corner  of  sections  5,  6,  7,  and  8,  run 
thence  successively  the  random  line  east  to  95,  nortli  to  97, 
and  west  to  99,  and  by  reverse  courses  back  on  true  lines  to 
the  southeast  corner  of  section  6,  establishing  the  quarter- 
section  corners,  and  noting  courses,  measurements,  and 
distances  as  prescribed  by  law. 

In  townships  contiguous  to  standard  parallels  the  above 
method  is  varied  as  follows:  In  every  township  sout]i  of  the 
principal  base  line  which  closes  on  a  standard  parallel,  the 
surveyor  will  begin  at  the  southeast  corner  of  the  township 
and  measure  westward,  establishing  the  half-mile  and  mile 
corners  and  noting  their  distance  from  the  preestablished 
corners.  He  will  then  proceed  to  subdivide  as  directed 
under  the  above  head. 

In  townships  north  of  the  principal  base  line -which  close 
on  the  standard  parallel,  the  section  lines  must  be  closed  on 
the  standard  parallel  with  true  meridian  lines  instead  of 
course  lines,  as  directed  for  townships  otherwise  situated ; 
and    the    connections    of    the    closing    corners    with    the 


LAND   SURVEYING.  703 

preestablished  standard  corners  are  to  be  ascertained  and 
noted. 

In  case  the  surveyor  is  unable  to  close  the  lines  on  account 
of  the  standard  not  having  been  run  for  some  reason,  as  be- 
fore mentioned,  he  will  then  plant  a  temporary  post  or  con- 
struct a  mound  at  the  end  of  the  sixth  mile,  thus  leaving 
the  lines  and  their  connections  to  be  finished  when  the 
standard  shall  have  been  run. 

1316.  Water  Frontage. — Departures  from  the  gen- 
eral system  of  dividing  land  have  been  authorized  by  law, 
especially  in  the  case  of  water  frontage. 

In  surveying  the  public  lands  of  Louisiana,  which  border 
on  rivers,  streams,  lakes,  and  bayous,  surveyors  were  author- 
ized to  divide  the  land  with  water  frontages  of  fifty-eight 
poles  and  running  back  four  hundred  and  sixty-five  poles  in 
depth, "and  of  such  shape  and  bounded  by  such  lines  as  the 
nature  of  the  country  will  render  practicable  and  most  con- 
venient."  Later,  authority  was  given  to  survey  lands  with 
two  acres  water  frontage  and  running  back  a  depth  of  forty 
acres,  tracts  so  surveyed  to  be  offered  for  sale  entire  in- 
stead of  in  half  quarter-sections.  In  localities  where  it 
would  best  subserve  the  interests  of  the  people  to  have 
fronts  on  the  navigable  streams  and  running  back  into  the 
uplands  for  timber,  surveyors  were  authorized  to  increase 
the  quantity  of  land  so  as  to  give  four  acres  frontage  and 
forty  acres  in  depth,  giving  tracts  of  160  acres,  but  in  so 
doing  they  were  only  to  survey  the  lines  between  every  four 
lots  (or  640  acres),  establishing  the  boundary  posts  or  mounds 
in  front  and  in  rear,  at  the  distances  requisite  to  secure  the 
quantity  of  160  acres  to  each  lot,  either  rectangularly  where 
practicable  or  at  oblique  angles  where  otherwise.  The  angle 
is  not  important  so  long  as  the  principle  is  adhered  to  of 
making,  as  far  as  possible,  the  rear  lines  square  with  the 
regular  sectioning. 

1317.  Meandering. — This  name  is  applied  to  the 
usual  mode  of  traversing  or  surveying  a  navigable  stream. 
The  instructions  for  this  work  are  in  part  as  follows:    Both 


704  LAND    SURVEYING. 

banks  of  navigable  rivers  are  to  be  meandered  by  taking  the 
courses  and  distances  of  their  sinuosities  and  the  same  are 
to  be  entered  in  the  meander  field  book.  At  those  points 
where  either  the  township  or  section  lines  intersect  the 
banks  of  a  navigable  stream,  posts,  or,  where  necessary, 
mounds  of  earth  or  stone  are  to  be  established  at  the  time  of 
running  these  lines.  These  are  called  "  meander  corners," 
and,  in  meandering,  the  surveyor  will  commence  at  one  of 
these  corners  on  the  township  line,  coursing  the  banks  and 
measuring  the  distance  of  each  course  from  the  commencing 
corner  to  the  next  "meander  corner "  upon  the  same  or 
another  boundary  of  the  same  township,  carefully  noting 
intersections  with  all  the  intermediate  meander  corners. 
By  the  same  method  meander  the  opposite  banks  of  the 
river. 

The  crossing  distance  between  the  meander  corners  on  the 
same  line  is  to  be  ascertained  by  triangulation,  in  order  that 
the  river  may  be  protracted  with  entire  accuracy.  The 
particulars  are  to  be  given  in  the  field  notes.  The  courses 
and  distances  on  meandered  navigable  streams  are  the  bases 
for  the  calculation  of  the  true  areas  of  the  tracts  of  land 
(sections,  quarter-sections,  etc.),  known  to  the  law  as 
fractional  and  bounding  on  such  streams. 

The  surveyor  is  also  to  meander,  in  manner  aforesaid,  all 
lakes  and  deep  ponds  of  the  area  of  twenty-five  acres  and 
upwards,  also  navigable  bayous. 

As  traverse  tables  are  generally  calculated  to  15'  angles, 
it  is  advisable  to  make  meander  courses  read  to  quarter 
degrees  instead  of  intermediate  minutes,  except  in  closing  or 
where  the  extreme  length  of  a  side  of  a  lake  or  stream  falls 
in  one  course. 

The  precise  relative  position  of  islands  in  a  township  made 
fractional  by  the  river  in  which  they  are  situated  is  to  be 
determined  trigonometrically.  To  meander  islands  crossed 
by  government  lines,  meander  corners  are  previously  estab- 
lished at  opposite  points  on  the  shore  of  the  island,  and  the 
meanders  run  from  one  to  the  other.  Should  the  island  not 
be  crossed  by  a  line,  measure  a  special  base  line  from  the 


LAND    SURVEYING.  705 

meander  corner  nearest  to  the  island,  triangulating  to  and 
establishing  at  any  convenient  point  on  the  island  a  special 
meander  corner  from  and  to  which  the  meanders  of  the  island 
start  and  close, 

1318.  Marking  Lines. —  All  lines  on  which  are  to 
be  established  the  legal  corner  boundaries  are  to  be  marked 
after  this  method,  viz. :  Those  trees  which  may  intercept 
the  line  must  have  two  chops  or  notches  cut  on  each  side  of 
them  without  any  other  marks  whatever;  these  are  called 
sight  trees  or  line  trees.  A  sufficient  number  of  other  trees 
standing  nearest  to  the  line  on  either  side  of  it  are  to  be 
blazed  on  two  sides  diagonally  or  quartering  towards  the  line, 
in  order  to  render  the  line  conspicuous  and  readily  traced, 
the  blazes  to  be  opposite  to  each  other,  coinciding  in  direc- 
tion with  the  line  where  the  trees  stand  very  near  it,  and 
to  approach  nearer  each  other  the  further  the  line  passes 
from  the  blazed  trees.  Due  care  must  ever  be  taken  to  have 
the  line  so  well  marked  as  to  be  readily  followed. 

1319.  Marking  Corners. — After  a  true  coursing 
and  most  exact  measurements,  the  corner  boundary  is  the 
consummation  of  the  work  for  which  all  the  previous  pains 
and  expenditure  have  been  incurred.  A  boundary  corner  in 
a  timbered  country  is  to  be  a  tree,  if  one  be  found  at  the 
precise  spot;  and  if  not,  di post  is  to  be  planted  thereat,  and 
the  position  of  the  corner  post  is  to  be  indicated  by  trees 
adjacent  (called  bearing  trees),  the  angular  bearings  and 
distances  of  which  from  the  corner  are  facts  to  be  ascertained 
and  recorded  by  the  surveyor.  In  a  region  where  stones 
abound,  the  corner  boundary  will  be  a  small  monument  of 
stones  alongside  of  a  single  marked  stone  for  a  township 
corner  and  a  single  stone  for  all  other  corners. 

In  a  region  where  neither  timber  nor  stone  is  available, 
the  corner  will  be  a  mound  of  earth  of  prescribed  size 
varying  to  suit  the  case. 

When  posts  are  used,  their  length  and  size  must  be  pro- 
portional to  the  importance  of  the  corner,  whether  township, 
section,  or  quarter-section  post. 


706 


LAND   SURVEYING. 


Township  corner  posts  are  three  inches  square  and  set  at 
least  twenty-four  inches  above  ground. 

Where  a  township  post  is  at  a  corner,  common  to  four 
townships,  it  is  to  be  set  in  the  ground  diagonally,  as  shown 
«  in  Fig.  311,  and  the  cardinal  points  of  the  compass 
indicated  by  lines  cut  or  sawed  out  of  its  top  at 
p^-^  least  one-eighth  of  an  inch  deep,  as  shown  in  the 
figure.  On  each  face  of  the  post  is  to  be  marked 
Fig.  311.  the  number  and  range  of  the  particular  township 
which  it  faces.  Thus,  if  the  post  be  a  common  boundary 
to  four  townships,  viz.,  one  and  two  south  of  the  base  line 
and  range  two  west,  and  also  one  and  two  south  of  the 
base  line  and  range  three  west,  the  face  markings  will  be  as 
follows : 


( 

R.  2  W 

From  N  to  E  ^ 

T.  1  S 

( 

S31 

/ 

3  W 

From  N  to  W  - 

1  S 

1 

36 

1 

2  W 

From  E  to  S  - 

2S 

1 

6 

( 

3  W 

From  W  to  S  - 

2S 

( 

1 

R3W 
TIS 


R2W 
TIS 


R3W  R2W 

T2S      T2S 

Pig.  812. 


The  position  of  the  post  which  is  here  taken  as  an 
example  is  shown  in  Fig.  312. 

These  marks  are  neatly  chiseled  into  the  wood,  and  are 
also  marked  with  red  chalk.  The  number  of  the  sections 
which  they  respectively  face  will  also  be  marked  on  the 
township  post.  • 

Section  or  mile  posts,  being  corners  of  sections,  when 
they  are  common  to  four  sections,  are  to  be  set  diagonally 
in  the  earth  (in  the  manner  provided  for  township  posts), 
and  with  similar  marks  cut  in  the  top  to  indicate  the  car- 
dinal points  of  the  compass,  while  on  each  side  of  the  post  is 


LAND    SURVEYING.  707 

cut  the  number  of  the  particular  section  which  the  side 
faces.  Also,  on  one  side  is  to  be  marked  the  number  of  its 
township  and  range.  To  make  such  marks  more  conspicuous 
and  durable,  red  chalk  is  applied.  A  quarter-section  or 
half-mile  post  is  to  have  no  other  mark  than  ^  S  to  indicate 
what  it  stands  for. 

Township  posts  are  to  be  notclicd  with  six  notches  on 
each  edge  or  angle  corresponding  to  the  cardinal  points  of 
the  compass.  All  mile  posts  on  township  lines  must  have 
as  many  notches  on  opposite  angles  as  they  are  miles  dis- 
tant from  the  corresponding  township  corners.  Each  of 
the  posts  at  the  corners  of  sections  in  the  interior  of  a  town- 
ship must  have  on  their  four  angles,  corresponding  to  the 
cardinal  points,  as  many  notches  as  they  are  miles  distant 
from  the  corresponding  township  corners.  The  four  sides 
of  the  post  will  indicate  the, numbers  of  the  sections  which 
they  respectively  face.  Should  a  tree  be  found  at  the  place 
of  any  corner  it  will  be  marked  and  notched  in  the  manner 
before  described  and  will  serve  in  place  of  a  post;  the  kind 
of  tree  and  the  diameter  must  be  given  in  the  field  notes. 

The  position  of  all  corner  posts  or  corner  trees  of  what- 
ever description,  which  may  be  established,  is  to  be  perpet- 
uated in  the  following  manner,  viz. :  From  such  post  or  tree, 
the  courses  shall  be  taken  and  the  distances  measured  to  two 
or  more  adjacent  trees  in  opposite  directions  as  nearly  as 
may  be,  which  are  called  bearing  trees,  and  are  to  be  blazed 
near  the  ground  with  a  large  blaze  facing  the  post  and  hav- 
ing one  notch  in  it,  neatly  and  plainly  made  with  an  ax, 
square  across,  and  a  little  below  the  middle  of  the  blaze. 
The  kind  of  tree  and  the  diameter  of  each  are  facts  to  be 
clearly  set  forth  in  the  field  book. 

On  each  bearing  tree  the  letters  B.  T.  must  be  distinctly 
cut  into  the  wood  in  the  blaze  a  little  above  the  notch  or 
on  the  bark,  with  the  number  of  the  range,  township,  and 
section. 

At  all  township  corners  and  at  all  section  corners  on 
range  or  township  lines  y<7//r  bearing  trees  are  to  be  marked 
in  this  manner,  one  in  each  of  the  adjoining  sections. 


708  LAND   SURVEYING. 

At  interior  section  corners  four  trees,  one  to  stand 
within  each  of  the  four  sections  to  which  such  corner  is  com- 
mon, are  to  be  marked  in  the  manner  aforesaid  if  such  be 
found. 

From  quarter-section  and  meander  corners,  two  bear- 
ing trees  are  to  be  marked,  one  within  each  of  the  adjoining 
sections.  Stones  at  township  corners  (a  small  monument  of 
stones  being  alongside  thereof)  must  have  six  notches  cut 
with  a  pick  or  chisel  on  each  edge  or  side  towards  the  car- 
dinal points;  and  where  used  as  corners  in  the  interior  of  a 
township,  they  will  also  be  notched  with  a  pick  or  chisel  to 
correspond  with  the  directions  given  for  notching  posts 
similarly  situated. 

Stones  when  used  as  quarter-section  corners  will  have 
\  cut  on  them,  on  the  zvest  side  in  nortJi  and  soutJi  lines,  and 
on  the  nortJi  side  in  east  and  zvcst  lines. 

Wherever  bearing  trees  are  not  found,  mounds  of  earth 
or  stone  are  to  be  raised  around  posts  on  which  the  corners 
are  to  be  marked  in  the  manner  aforesaid.  Wherever  a 
mound  of  earth  is  adopted,  the  same  will  present  a  pyra- 
midal shape.  At  its  base  on  the  earth's  surface  a  quadran- 
gular trench  will  be  dug ;  a  spade  deep  of  earth  being  thrown 
up  from  the  sides  of  the  line  outside  the  trench,  so  as  to 
form  a  continuous  elevation  along  its  outer  edge.  In  mounds 
of  earth  common  to  four  townships  or  four  sections,  they 
will  present  the  angles  of  the  quadrangular  trench  diagonally 
to  the  cardinal  points.  In  mounds  common  only  to  two 
townships  or  two  sections,  the  sides  of  the  trench  will  face 
the  cardinal  points.  Prior  to  piling  up  the  earth,  in  a 
cavity,  formed  at  the  corner  boundary  point,  is  to  be 
deposited  a  stone,  or  a  portion  of  charcoal;  or  a  charred 
stake  is  to  be  driven  twelve*  inches  down  into  such  center 
point  to  be  a  witness  for  the  future.  The  surveyor  is 
further  specially  enjoined  to  plant  midway  between  each 
pit  and  the  trench  seeds  of  some  tree,  those  of  fruit  trees 
adapted  to  the  climate  being  always  to  be  preferred. 

Double  corners  are  to  be  found  nowhere  except  on  the 
standard  parallels  or  correction  lines  whereon  are  to  appear 


LAND    SURVEYING.  709 

both  the  corners  which  mark  the  intersection  of  the  lines 
which  close  thereon  and  those  from  which  the  surveys  start 
in  the  opposite  direction. 

The  corners  which  are  established  on  the  standard 
parallel  at  the  time  of  running  it  are  to  be  known  as 
^'-  standard  corners,'"  and  in  addition  to  all  the  ordinary- 
marks  (before  described)  they  will  be  marked  with  the 
letters  S.  C.     The  closing  corners  will  be  marked  C.  C. 

1320.  Field  Books. — There  are  several  field  books, 
viz. : 

1.  Field  Books  for  the  meridian  and  base  lines,  show- 
ing the  establishment  of  toiunship,  section,  or  mile,  and 
quarter-section,  or  half-mile  boundary  corners  thereon ;  with 
the  crossings  of  streams,  ravines,  hills,  and  mountains;  the 
character  of  the  soil,  timber,  minerals,  etc.  These  notes 
will  be  arranged  in  series  by  mile  stations  consecutively 
from  number  one  to  number . 

2.  Field  Books  for  the  standard  parallels  or  correction 
lines,  showing  the  establishment  of  the  township,  section,  and 
quarter-section  corners,  besides  exhibiting  the  topography  of 
the  country  on  line  as  required  on  the  base  and  meridian 
lines. 

3.  Field  Books  for  exterior  lines  of  townships,  showing  the 
establishment  of  the  corners  on  line,  and  the  topography  as 
aforesaid. 

4.  Field  Books  for  the  subdivision  of  townships  into 
sections  and  quarter-sections;  at  the  close  whereof  will 
follow  the  notes  of  the  meanders  of  navigable  streams. 
Those  notes  will  also  show  by  ocular  observation  the  estima- 
ted rise  and  fall  on  the  line.  A  description  of  the  timber, 
undergrowth,  surface  soil,  and  minerals  upon  each  section 
line  is  to  follow  the  notes  thereof,  and  not  be  intermixed 
with  them. 

5.  The  Geodetic  Field  Book,  comprising  all  triangulations, 
angles  of  elevation  and  depression,  leveling,  etc. 

1321.  Retracing  Old  Lines. — The  original  surveys 
of  lands  in  the  older  States  of  the  American  Union  were 


710 


LAND   SURVEYING. 


imperfectly  made  and  full  of  errors.  This  was  owing  to  two 
principal  causes;  viz.,  the  cheapness  of  the  lands  and  the 
lack  of  skill  in  the  surveyors.  Boundary  lines  described  in 
deeds  and  shown  in  maps  as  straight  are  found  to  be  crooked 
on  the  ground;  tracts  contain  less  or  more  land  than 
called  for  in  descriptions.  Records  of  adjoining  tracts  make 
one  to  overlap  another  or  leave  an  unclaimed  gore  between 
them.  These  discrepancies  and  blunders  often  render  the 
work  of  the  surveyor,  when  retracing  old  boundaries  or 
establishing  corners,  exceedingly  difficult,  and  great  tact  and 
judgment  are  often  necessary  in  making  amicable  and  satis- 


FiG.  318. 

factory  adjustments  of  contending  claims.  In  general,  old 
boundaries,  such  as  line  trees,  stone  monuments,  and  fences 
are  accepted  as  holding  ;  but,  before  retracing  lines  the 
surveyor  should,  if  possible,  secure  the  consent  of  adjacent 
owners  to  abide  by  such  monuments  and  boundaries,  irre- 
spective of  the  lines  or  quantities  called  for  in  contracts  or 
deeds.  It  must  be  borne  in  mind  that  the  bearings  of  lines 
are  each  year  undergoing  a  slight  change  which,  in  a  long 
period,  amounts  to  several  degrees,  and  if  the  lines  were  re- 
run according  to  original  bearings  as  given  in  descriptions, 
they  would  enclose  a  tract  differing  widely  from  that  in- 
cluded in  the  original  survey.     The  surveyor  must  accord- 


LAND   SURVEYING. 


711 


ingly  determine  the  amount  of  magnetic  variation  or  change 
which  has  taken  place  between  the  time  of  the  original 
survey  and  the  date  of  the  survey  about  to  be  made,  and 
having  determined  such  change  or  variation,  he  must  make 
the  original  bearings  conform  to  the  calculated  variation 
before  commencing  the  survey. 

Fig.  313  illustrates  the  effect  of  magnetic  variation  in 
altering  the  direction  of  lines.  The  figure  A  B  C  D  Ogives 
the  outline  of  a  tract  according  to  the  original  survey,  and 
A  B'  C  D'  E'  the  relative  directions  of  the  boundaries  when 
resurveyed  with  the  original  bearings,  there  having  been 
during  the  intervening  time  a  change  in  magnetic  variation 
of  3°  west. 

Let  columns  1,  2,  and  3  in  the  accompanying  diagram 
give  the  courses,  original  bearings,  and  distances,  and  col- 
umn 4  the  cor-   

rected  bearings 
which  the  original 
boundaries  will 
have,  when  allow- 
ance  has  been 
made  for  the  mag- 
netic variation. 
When  the  north 
end  of  the  needle 
has  been  moving  westerly,  i.  e.,  when  the  variation  or  chatige 
is  west,  the  corrected  or  present  bearings  will  be  the  sums  of 
the  change  and  the  old  bearings  which  were  northeasterly  or 
soiitJnvesterly  and  the  differences  of  the  change  and  the  old 
bearings  which  were  northwesterly  or  southeasterly ;  when 
the  variation  or  change  is  easterly^  the  corrected  or  present 
bearings  will  be  the  differences  of  the  change  and  the  old 
bearings  which  were  northeasterly  or  southwesterly  and  the 
sujus  of  the  change  and  the  old  bearings  which  were  north- 
westerly or  southeasterly. 

It  will  be  seen,  by  reference  to  Arts.  1211  and  1212, 
that  declination  is  the  reverse  of  i>ariation,  i.  e. ,  a  west  decli- 
nation results  when  the  variation  or  movement  of  the  N  end 


1 

2 

3 

4 

Courses. 

Bearings. 

Distances. 

Corrected 
Bearings. 

A  B 

N68°00'   E 

210 

N7r00'   E 

B  C 

S  73°  00'   E 

200 

S  70°  00'   E 

CD 

S     8°  00'   E 

162 

S     5°  00'    E 

D  E 

S  87°  00'  W 

326 

S  90°  00'  W 

EA 

N  28°  00'  W 

176 

N  25°  00'  W 

712  LAND    SURVEYING. 

of  the  needle  is  to  the  east,  and  <'rtj/ declination  results  when 
the  movement  of  the  N  end  of  the  needle  is  to  the  west. 
By  this  rule  the  bearings  given  in  column  4  are  obtained. 
Before  commencing  the  survey,  the  surveyor  should  cor- 
rect all  the  bearings  and  write  them  out  together  with  the 
original  bearings  in  their  proper  order. 

1322.  How  to  Determine  Magnetic  Variation. — 

If  the  date  of  the  original  survey  is  known,  the  amount  of 
variation  may  be  determined  from  published  tables  giving 
the  yearly  variation  for  different  sections  of  the  country,  but 
the  date  of  the  survey  is  often  omitted.  The  date  of  the 
deed  must  not  be  taken  as  the  date  of  the  survey. 

If  one  of  the  original  boundaries  remains  unchanged,  the 
magnetic  variation  can  be  determined  at  once  by  taking  the 
present  bearing  of  the  line.  The  difference  between  the 
present  bearing  and  that  of  the  original  survey  is  the  re- 
quired correction.  The  corrections  are  then  to  be  made  in 
the  original  bearings  and  the  resulting  courses  run  out. 
Where  the  measurements  fall  short  of  or  overrun  the 
original  measurements,  corrections  must  be  made,  locating 
the  original  corners  if  they  can  be  found  or  establishing  new 
ones,  and,  if  possible,  to  the  mutual  satisfaction  of  adjoining 
proprietors. 

1323.  Establishing  New  Boundaries. — Where  the 
description  and  map  show  a  boundary  to  be  a  straight  line 
and  the  actual  boundary  is  found  to  be  crooked,  it  is  a  good 
policy  to  establish  a  new  and  straight  boundary  by  the  prin- 
ciple of  "give  and  take,"  providing  adjoining  owners  will 
agree  to  the  adjustment. 

Fig.  314  illustrates  the  principle  which  is  frequently  em- 
ployed in  correcting  such  boundaries. 

M^  D 


c 

Fig.  314. 
Let  A  and  E  be  two  corners  and  let  the  boundary  line 
joining  them  be  described  and  shown  in  the  map  as  a  straight 


LAND   SURVEYING.  713 

line.  Let  the  irregular  line  A  B  CD  £' represent  the  actual 
boundary.  It  is  evident  that  the  dotted  straight  line  A  E 
may  be  substituted  for  the  irregular  line  A  B  C  D  E,  and 
would  equitably  divide  the  adjoining  properties.  The  prin- 
ciple of  give  and  take  is  applied,  the  adjoining  owners  ma- 
king exchanges  .of  equal  areas. 

The  location  of  the  new  boundary  is  determined  by  ma- 
king a  careful  survey  of  the  old  boundary  and  platting  it  to  a 
large  scale;  a  fine  thread  is  then  stretched  on  the  plat  and  a 
line  of  division  made  as  closely  as  may  be  estimated  by  the 
eye.  The  areas  of  the  equalizing  triangles  are  then  calcu- 
lated by  scaling  their  dimensions,  and  if  they  do  not  balance 
the  dividing  line  can  readily  be  shifted  until  the  desired 
result  is  obtained.  The  line  is  then  measured  on  the  ground 
and  permanent  corners  established.  Where  the  boundary 
is  in  woodland,  careful  search  must  be  made  for  line  and 
bearing  trees.  Blaze  marks  are  very  enduring,  being  easily 
recognized  on  some  varieties  of  trees  after  a  lapse  of  a 
quarter  of  a  century. 

1324.  Lost  and  Obliterated  Corners. — Corner 
monuments  of  perishable  material,  such  as  wooden  posts, 
decay  and  in  time  become  obliterated.  A  pile  of  stones, 
which  is  commonly  used  as  a  corner,  may  become  scattered, 
and,  unless  permanent  witnesses  remain,  it  may  be  a  difficult 
matter  to  restore  the  landmark.  The  most  enduring  wit- 
nesses are  live  trees  which  are  disposed  as  shown  in  Fig.  315. 

Three  trees  facing  the  corner  are  chosen  ;  in  each  tree 
three  notches  are  cut  in  the  side  facing  the  corner,  and  the 
bearing  and  distance  from  each  to  the  corner  are  recorded  in 
the  notes.  A  sketch  is  made  in  the  note  book  giving  the 
relative  positions  of  the  corner  and  the  witness  trees.  When 
the  corner  is  lost,  but  the  witness  trees  still  remain,  the  cor- 
ner is  restored  by  describing  intersecting  arcs  from  the  wit- 
ness trees  as  centers  with  radii  equal  to  the  given  distances 
from  the  original  corner.  Where  both  corner  and  witnesses 
are  gone,  it  is  best  to  run  from  both  directions  towards  the 
missing  corner,  placing  the  corner  at  the  intersection  of  the 


714 


LAND    SURVEYING. 


lines.  The  surveyor  need  not  expect  to  find  his  measure- 
ments agree  with  those  in  original  surveys,  but  he  can  save 
his  successor  much  annoyance  and  trouble  by  careful  and 
accurate  work.  He  should  always  give  both  in  map  and  in 
description  the  exact  date  of  the  survey;  the  direction  of 


Fig.  315. 


courses  should  also  be  given  both  in  writing  and  figures,  and 
the  corners  should  be  fully  described.  A  stone  monument 
is  the  best  corner,  and  should  always  be  used  where  the 
material  is  available. 


AREAS. 
1325.  The  area  of  a  surface  is  its  superficial  content. 
In  the  surveying  of  public  lands  all  measurements  are  made 
with  the  surveyor's  chain,  commonly  known  as  Gunter's 
chain,  from  the  name  of  the  inventor.  It  is  GO  feet  in  length 
and  contains  100  links,  each  7.92  inches  long.  At  each 
interval  of  ten  links  a  brass  tag  is  attached  with  tally  points 
similar  to  those  on  the  engineer's  chain  described  in  Art. 
1214.  Tables  of  surveyor's  linear  and  square  measure  are 
given  in  Arts.  209  and  211.  For  land  areas  the  unit  of 
measurement  is  the  square  foot  =  144  square  inches,  though 


LAND   SURVEYING.  715 

areas  of  considerable  extent  are  usually  expressed  in  acres. 
An  acre  contains  43,500  square  feet  of  surface.  Rectangular 
areas  are  determined  by  multiplying  the  length  in  feet  by 
the  breadth  in  feet,  and  dividing  the  product  by  43,500, 
which  gives  the  area  in  acres. 

In  surveys  of  farms  or  larger  tracts,  dimensions  are  given 
in  chains  and  links.  The  product  of  such  dimensions  is  in 
square  chains,  which,  divided  by  10  (the  number  of  square 
chains  in  an  acre),  gives  the  area  in  acres. 

Example. — A  rectangular  piece  of  land  is  1,060  feet  in  length  by 
820  feet  in  breadth ;  required,  the  area. 

Solution.—  1,060  x  820  =  869,200  sq.  ft.  869,200  -h  43,560  =  19.954 
acres.     Ans. 


DIFFERENT   METHODS   OF    COMPUTING   AREAS. 

1326.     By    Dividing    the    Plat  into  Triangles.— 

Farms,  especially  in  the  older  States  of  the  Union,  are  com- 
monly of  irregular  form.  The  readiest  and — where  the 
measurements  have  been  accurately  made — a  sufficiently 
accurate  method  of  determining  areas  is  as  follows  :  Make 
an  accurate  plat  of  the  tract  to  as  large  a  scale  as  may  be 
conveniently  used.  Divide  the  resulting  figure,  an  irregular 
polygon,  into  triangles,  making  their  sides  of  as  nearly  equal 
length  as  possible.  It  is  evident  that  the  sum  of  the  areas 
of  the  several  triangles  into  which  the  polygon  is  divided  is 
equivalent  to  the  area  of  the  polygon.  This  mode  of  calcu- 
lating area  is  illustrated  in  Fig.   316. 

Let  the  irregular  polygon  A  B  C  D  E  Fhe  the  outline  of 
a  tract  of  land  the  area  of  which  is  required.  Draw  the 
diagonals  B  F,  C  F,  and  C  E,  dividing  the  figure  into  four 
triangles,  the  combined  area  of  which  is  equal  to  the  area  of 
the  polygon.  From  the  vertexes  A,  B,  D,  and  E  drop  the 
perpendiculars  A  G,  B  //,  D  K,  and  E  L  upon  the  opposite 
bases  of  the  triangles.  The  lengths  of  the  several  bases  and 
altitudes  are  measured  with  the  scale  and  the  areas  of  the 
several  triangles  calculated  by  the  rule  :  the  area  of  a  trian- 
gle is  equal  to  one-half  the  product  of  its  base  and  altitude. 


71G 


LAND    SURVEYING. 


The  sum  of  the  areas  of  the  several  triangles  is  equal  to  the 
area  of  the  polygon. 


Fig.  316. 


1327.     By  Dividing  the  Plat  into  Trapezoids. —A 

plat   of  the  area  having  been  made,  it  may  be  resolved  into 


trapezoids  by  either  of  the  methods  shown  in  Figs.  317  and 
318.  In  Fig.  317  the  line  A  N  is  drawn  parallel  to  B  C,  and 
the  lines  B  M,  K  H,  and  E  L  are  drawn  perpendicular  to 
A  H,  dividing  the  figure  into  trapezoids  and  the  triangle 
H  D  K.  The  area  of  each  trapezoid  is  equal  to  one-half  the 
sum  of  its  bases  multiplied  by  its  altitude,  and  the  sum  of 
their  areas  together  with  the  area  of  the  triangle  is  equiva- 
lent to  the  area  of  the  polygon  A  B  C  D  E  F.  In  Fig.  318 
a  base  line  H  Pis  drawn,  and  from  each  angle  of  the  polygon 
perpendiculars  are  drawn  to  it.  The  sum  of  the  areas  of  the 
three  trapezoids  A  B  K  H,B  C  N  K,  C  D  P  N  is  found,  and 


LAND    SURVEYING. 


717 


from  that  sum,  the  sum  of  the  areas  of  the  trapezoids 
A  G  L  //,  G  F  M  L,  F  E  O  M,  and  E  D  P  O  \s  subtracted. 
The  difference  of  these  sums  is  the  area  of  the  polygon 
A  B  C  D  E  FG. 


LATITUDES  AND    DEPARTURES. 

1328.  Definitions. — The  latitude  of  a  point  is  its 
distance  north  or  south  of  some  '^parallel  of  latitndc"  or 
line  running  cast  and  lucst.  The  longitude  of  a  point  is  its 
distance  east  or  west  of  some  meridian  or  line  running  north 
and  south. 

The  meridian  from  which  the  longitude  of  a  point  is 
reckoned  is  the  magnetic  meridian. 

The  distance  which  one  end  of  a  line  is 
due  north  or  south  of  the  other  end  is  called 
the  latitude  of  that  line. 

The  distance  which  one  end  of  -a  line  is 
due  east  or  west  of  the  other  end  is  called 
the  departure  of  that  line. 

The  latitude  and  departure  of  a  line  and 
its  determination  are  explained  in  Fig.  319. 
Let  A  B  he  the  given  line  whose  length  and 
angle  with  the  magnetic  meridian  A^  5  is 
known,  and  whose  latitude  and  departure 
are  required.  From  B  draw  B  C  perpen- 
dicular to  N  S^  forming  the  right-angled  triangle  A  C  B,'\x\. 
which  the  sides  C  A  and  C  B  about  the  right  angle  are,  re- 
spectively, the  latitude  and  the  departure  of  the  line  A  B. 
Then, 

A  C  ^=-  A  B  y,  cos  bearing,  and 
B  C  ^  A  B  X  sin  bearing; 

that  is,  the  latitude  is  equal  to  the  product  of  the  cosine  of 
the  bearing  and  the  length  of  the  course;  and  the  departure 
is  equal  to  the  product  of  the  sine  of  the  bearing  and  the 
length  of  the  course. 

Let  A  />' =  400  feet  and  the  bearing  of  A  B,  i.  e.,  the 
angle  B  A  C=  30°.     Then,  latitude  A  C=  co.)  30"  X  400  = 


Fig.  319. 


718  LAND   SURVEYING. 

.86G03   X   400  =    346.412   ft.,    and   departure   B   C  =  sin 
30°  X  400  =  .50000  X400  =  200  ft. 

If  the  course  be  northerly,  the  latitude  will  be  north, 
marked  +  ,  and  be  additive;  if  southerly,  it  will  be  marked 
— ,  and  be  subtractive.  If  the  course  be  easterly  the 
departure  will  be  east,  marked +,  and  be  additive;  if 
westerly,  the  departure  will  be  west,  marked—,  and  be 
subtractive. 

1329.  Traverse  Tables. — The  latitude  and  departure 
of  any  distance  for  any  bearing  can  be  found  by  a  table 
of  natural  sines  and  cosines,  but  for  facilitating  work 
special  tables,  called  traverse  tables,  have  been  prepared. 
They  usually  give  the  latitude  and  departure  for  any  bear- 
ing to  each  quarter  of  a  degree  and  for  distances  from 
1  to  9. 

To  t(se  the  tables  (see  traverse  tables,  or  Latitudes  and 
Departures  of  Courses),  find  the  number  of  degrees  in  the 
bearing  in  the  left-hand  column  if  the  bearing  be  less  than 
45°,  and  in  the  right-hand  column  if  the  bearing  be  greater 
than  45°.  The  numbers  on  the  same  line  running  across 
the  page  are  the  latitudes  and  departures  for  that  bearing 
and  for  the  respective  distances,  1,  2,  3,  4,  5,  6,  7,  8,  9, 
which  appear  at  the  top  and  bottom  of  the  pages,  and  which 
may  be  taken  to  represent  links,  rods,  feet,  chains,  or  any 
other  unit.  Thus,  if  the  bearing  be  10°  and  the  distance 
4,  the  latitude  will  be  3.939  and  the  departure  .G95;  with 
the  same  bearing,  and  the  distance  8,  the  latitude  will  be 
7.878  and  the  departure  1.389,  or  double  the  latitude  and 
departure  for  the  distance  4.  Any  distance,  however  great, 
can  have  its  latitude  and  departure  readily  obtained  from 
this  table,  since,  for  the  same  bearing,  the  latitude  and 
departure  are  directly  proportional  to  the  distance  because 
of  the  similar  triangles  which  they  form.  Hence,  the  lati- 
tude and  departure  for  80  is  ten  times  the  latitude  and 
departure  for  8,  and  is  found  by  moving  the  decimal  point 
one  place  to  the  right;  that  for  500  is  100  times  the  latitude 
and  departure  for  5,  and  is  found  by  moving  the  decimal 


LAND    SURVEYING.  719 

point  two  places  to  the  right,  and  so  on.  By  moving  the  decimal 
point  one,  two,  or  more  places  to  the  right  the  latitude  and 
departure  may  be  found  for  any  multiple  of  any  number 
given  in  the  table.  In  finding  the  latitude  and  departure 
for  any  number  such  as  453,  the  number  is  resolved  into 
three  numbers,  viz.:    40  0      and  the  latitude  and  departure 

5  0      for  each  taken  from  the  table 
3      and  then  added  together. 

453 

We  thus  obtain  the  following 

Rule.—  Write  dozvn  the  latitude  and  departure,  neglecting 
the  decimal  points,  for  the  first  figure  of  tJie  given  distance; 
write  under  them  the  latitude  and  departure  for  the  second 
figure,  setting  them  one  place  further  to  the  right;  under 
these  place  the  latitude  and  departure  for  the  third  figure, 
setting  them  one  place  still  further  to  the  right,  and  so 
continue  until  all  the  figures  of  the  given  distance  have  been 
used ;  add  these  latitudes  and  departures  and  point  off  on  the 
right  of  their  sums  a  ?iumber  of  decimal  places  equal  to  the 
number  of  decimal  places  to  which  the  tables  being  used  are 
carried;  the  resulting  numbers  will  be  the  latitude  and  de- 
parture of  the  given  distance  in  feet,  links,  chains,  or  whatever 
unit  of  measurement  is  adopted. 

Example. — A  bearing  is  16°  and  the  distance  725;  what  is  the  lati- 
tude and  departure  ? 

Distances.                           Latitudes.  Departures. 

700                              6729  1929 

20                                 1923  0551 

5  .                          4806  1378 


725  6  9  6.936  199.788 

Solution. — Taking  the  nearest  whole  numbers  and  rejecting  the 
decimals,  we  find  the  latitude  and  departure  to  be  697  and  200. 

When  a  0  occurs  in  the  given  number  the  next  figure  must 
be  set  two  places  to  the  right,  as  in  the  following  example: 

Example. — The  bearing  is  22°  and  the  distance  907  feet;  required, 
the  latitude  and  departure. 


730 


LAND   SURVEYING. 


Solution. — 

Distances. 

Latitudes. 

Departures. 

900 

8  34  5 

3371 

7 

6490 

2  622 

907 

840.990 

3  3  9.722 

Here  the  place  of  0  in  both  the  distance  column  and  in  the  latitude 
and  departure  columns  is  occupied  by  a  dash  — .     Rejecting  the  deci- 
mals, the  latitude  is  841  feet 
^■"'  and  the  departure  340  feet. 

When  the  bearing  is  more 
than  4~)°,  the  names  of  the 
columns  must  be  read  from 
the  bottom  of  the  page.  The 
latitude  of  any  bearing,  as 
60°,  is  the  departure  of  its 
complement,  30';  and  the 
departure  of  any  bearing,  as 
30°,  is  the  latitude  of  its 
complement,  60\  This  will 
be  readily  understood  from 
an  inspection  of  Fig.  320,  in 
which  if  A' 5  be  the  mag- 
netic meridian  and  BOA  =  60^  the  bearing,  then  A  O  \s  the  latitude 
and  A  B  the  departure.  If,  now,  6>  C  be  made  the  meridian  and 
i? 0(7  =30°  (the  complement  of  BOA)  the  bearing,  then  O  C  (the 
equal  of  A  B)  is  the  latitude,  and  B  C  (the  equal  of  A  O)  the  departure. 

Example. — Let  O  B  =  1,326  feet,  and  its  bearing  =  60°. 
Solution. — 

Distances.  Latitudes.  Departures. 

1,000  0500  0866 

300  1500  2598 

20  1000  1732 

6  3  00  0  5196 

1326 


Fig.  330. 


663.000 


1148.316 


of 
and 


The  required  latitude  is  663  feet  and  the  departure  1,148  feet. 

Where   the  bearings    are  given   in  smaller   fractions 
degrees   than    is    found    in   the   table,    the    latitudes 
departures  can  be  found  by  interpolation. 

Traverse  tables  are  chiefly  employed  in  testing  the  accuracy 
of  surveys,  platting  them,  and  calculating  their  content. 

1330.     Testing    a   Survey. — When   a   surveyor   has 
completed  the  survey  of  a  field  or  farm  by  taking  bearings 


LAND    SURVEYING. 


721 


and  measuring  courses,  it  is  evident  that  he  has  gone  as  far 
north  as  south  and  as  far  east  as  west.  The  sum  of  the 
north  latitudes  shows  how  far  north  he  has  gone,  and  the 
sum  of  the  south  latitudes  shows  how  far  south  he  has  gone. 
The  sum  of  the  east  departures  shows  how  far  east  he  has 
gone,  and  the  sum  of  the  west  departures  shows  how  far  west 
he  has  gone.  Hence,  if  the  survey  has  been  correctly  made 
these  sums  will  be  equal  or  will  balance. 

The  entire  operation  of  testing  a  survey  is  illustrated  in 
the  following  example: 


Latitudes 

Departures. 

N  + 

S  - 

E  + 

w  - 

1 

N  34i°E 

273 

226 

154 

2 

N  35i°  E 

128 

10 

128 

, 

3 

S  56i°  E 

220 

121 

184 

4 

S  34i°  W 

353 

292 

199 

5 

N56i"  W 

320 

177 

267 

34r 

273 


56r 
220 


413 


5786 
2480 


112  6 
3940 
1  68J 


225.640   153.688 


1097 
1097 

12  0.6  7 


1673 
1673 

184.03 


5  6i° 
320 


1656 

1104 

176.64 


413 

35r 

128 


34r 

353* 


2502 
166! 


466. 

0079 
0157 
0621 


266.88 


466 

0997 
1994 
7975 


10.098      12  7.615 


2480         •  1688 
4133  2814 

2480  1681 


291.810       198.628 


Adding  up  the  north  and  south  latitudes  we  find  them  to 
exactly  balance  each  other,  as  do  the  east  and  west  departures, 
which  proves  the  survey  to  be  correct.  On  account  of  the 
inherent  defects  of  the  compass  and  the  errors  which  are 


7%2 


LAND   SURVEYING. 


liable  to  occur  in  measurement,  especially  on  rough  and 
extensive  areas,  it  is  but  rarely  that  the  survey  will  exactly 
balance.  A  moderate  discrepancy,  which  would  indicate 
what  may  be  called  unavoidable  errors,  will  be  allowable, 
and  the  survey  accepted  as  correct.  How  great  a  difference 
in  the  sums  of  the  columns  may  be  allowed  is  a  doubtful 
question.  Every  surveyor  of  experience  knows  the  average 
degree  of  accuracy  of  his  work,  and  will  readily  distinguish 
between  a  serious  error  and  an  allowable  inaccuracy. 

1331.  Balancing  a  Survey. — When  the  sums  of  the 
latitudes  and  of  the  departures  do  not  equal  each  other,  and 
yet  the  difference  does  not  indicate  any  error,  the  different 
latitudes  and  departures  are  modified  so  that  their  sums 
shall  be  equal.      This  process  is  called  balancing  the  survey. 

The  error  is  distributed  among  the  different  courses  in 
proportion  to  their  length  by  the  following 

Rule. — As  the  sum  of  all  the  courses  is  to  any  separate 
course^  so  is  the  ivJiole  difference  in  latitude  to  the  correction 
for  that  course.     A  similar  proportion  corrects  the  departures. 

An  example  illustrating  the  process  of  balancing  a  survey 
is  given  below.  In  this  example  four  separate  columns  are 
given  for  the  corrected  latitudes  and  departures.  In  prac- 
tice, however,  the  corrected  latitudes  and  departures  are 
written  in  red  ink  directly  above  the  original  ones,  which 
are  crossed  out  with  red  ink.  The  distances  given  are  in 
chains: 


sta- 
tions. 

Bearings. 

Dis- 
tances. 

Latitudes. 

De- 
partures. 

Corrected 
Latitudes. 

Corrected 

De- 
partures. 

N  + 

S- 

E  + 

W- 

N-f-l  S- 

E-l- 

W  - 

1 
2 

3 
4 

N   53°    E 
S    29rE 
S    31f °  W 
N   61=    W 

10.63 
4.10 
7.69 
7.13 

6.54 
3.46 

3.56 
6.54 

8.38 
2.03 

4.05 
6.24 

6.58 
3.48 

3.55 
6.51 

8.;m 

2.01 

4.08 
6.27 

29.55 

10.00 

10.10 

10.41 

10.29 

10.06 

10.06 

10.35 

10.35 

LAND    SURVEYING. 


723 


The  corrections  are  made  by  the  following  proportions; 


For  Latitudes. 

For  Departures. 

29.55 

.  10.63::  10  :  4  links. 

29.55  : 

10.63::  12  :  4  links. 

29.55 

4.10::  10:  1  link. 

29.55 

4.10::  12  :  2  links. 

29.55 

7.69::  10  :  Slinks. 

29.55  • 

7. 69::  12:  Slinks. 

29.55 

:    7.13::10:2  1inks. 

29.55 

7.13::  12:  3  links. 

10  12 

This  rule  should  not  always  be  strictly  followed,  especially 
if  one  line  has  been  measured  over  rough  and  broken  coun- 
try, while  the  others  have  been  measured  over  smooth  and 
open  ground.  In  such  a  case  the  greater  part  of  the  error 
will  probably  lie  in  the  rough  line,  and,  consequently,  it 
should  receive  the  larger  share  of  the  correction.  A  slight 
alteration  of  a  bearing  will  sometimes  balance  a  survey. 
This  may  be  done  where  an  obstructed  sight  has  probably 
caused  an  error  in  the  bearing. 

1332.  Application  of  Latitudes  and  Departures 
to  Platting. — Rule  three  columns,  one  for  stations,  the 
next  for  total  latitudes,  and  the  third  for  total  departures, 
as  shown  in  the  following  diagram. 

To  obtain  the  total  latitudes,  begin  at  any  station,  the 
extreme  east  or  west  one  is  preferable,  and  add  up  algebra- 
ically the  latitudes  of  the  following  stations,  observing  that 
north  latitudes  are  plus  (+)»  and  south  latitudes  minus  (  — ). 
In  the  same  manner  find  the  algebraic  sum  of  the  depar- 
tures for  the  different  stations,  placing  each  successive  sum 
opposite  its  proper  station. 

In  the  example  given  in  Art.  1330,  beginning  at  Station 
1,  we  obtain  the  fol- 
lowing results. 

The  work  is  proved 
to  be  correct  by  the 
latitudes  and  depar- 
tures for  Station  1 
coming  out  equal  to 
0.  To  apply  these 
total  latitudes  and  de- 
partures in  platting, 


Stations. 

Total  Latitudes 
from  Station  1. 

Total  Departures 
from  Station  1. 

1 

0.00 

0.00 

2 

+  2.26 

+  1.54 

3 

+  2.36 

+  2.82 

4 

+  1.15 

+  4.66 

5 

-1.77 

+  2.67 

1 

0.00 

0.00 

7U 


LAND   SURVEYING. 


we  draw  a  meridian  through  the  point  taken  as  Station  1, 
Fig.  321.  Scale  off  from  Station  1  upwards  on  this  meridian 
the  latitude  2.26  chains  to  A  and  to  the  right  from  A,  and 
perpendicularly  lay  off  the  departure  1.54  chains  to  Station 
2.  Join  1-3.  From  1  again  lay  off  the  latitude  2.3G  (  = 
2.26  +  10)  chains  to  B,  and  to  the  right  perpendicularly 
the  departure  2.82  (=  1.54  +  1.28)  chains  to  Station  3. 
Join   2-3,    and  proceed  in  like  manner   to   locate    Stations 


Fig.  321. 

.^  and  S,  laying  off  +  latitudes  above  Station  1  and  + 
departures  to  the  right  of  the  meridian,  and  —  latitudes 
below  Station  1  and  —  departures  to  the  left  of  the  merid- 
ian. The  principal  advantages  of  this  mode  of  platting 
are  rapidity  of  work,  the  fact  that  each  course  is  platted 
independently,  and  the  certainty  of  the  plats  closing,  pro- 
vided the  latitudes  and  departures  have  previously  been 
balanced. 

1333.  Calculating  the  Content.— The  survey  of  a 
field  or  farm  having  been  made  and  platted,  the  content  can 
always  be  found  by  dividing  the  plat  into  triangles,   and 


LAND    SURVEYING. 


725 


scaling  off  their  bases  and  perpendiculars  from  which  the 
contents  are  calculated.  This  and  other  methods  previously 
mentioned  are  only  approximate,  the  degree  of  accuracy 
depending  upon  the  largeness  of  the  scale  and  the  skill  of 
the  draftsman.  The  method  of  calculating  content  by 
latitudes  and  departures  is  perfectly  accurate,  and  does  not 
require  the  previous  preparation  of  a  plat. 

1334.  Definitions. — If  a  meridian  be  passed  through 
the  extreme  east  or  west  corner  of  a  field,  the  perpendicular 
distance  from  any  station  to  that  meridian  is  the  longitude 
of  that  station,  additive  or  plus  if  east  and  subtractive  or 


Fig.  322. 

minus  if  west.  The  distance  of  the  middle  point  of  any  line, 
such  as  the  side  of  the  field,  from  the  meridian  is  called  the 
longitude  of  that  side.  The  difference  of  the  longitudes 
of  the  two  ends  of  a  line  is  called  the  departure  of  the  line; 
the  difference  of  the  latitudes  of  the  two  ends  of  a  line  is 
called  the  Uititude  of  the  line. 


72G  LAND   SURVEYING. 

1335.     Longitudes.— Let    N    S,     Fig.    322,    be    the 

meridian  passing  through  the  extreme  westerly  station  of 
the  field  A  B  C  D  E.  From  the  middle  and  ends  of  each 
side  draw  perpendiculars  to  the  meridian.  These  perpendicu- 
lars will  be  the  longitudes  and  departures  of  the  respective 
sides.  The  longitude  F  G  of  the  first  course  A  B  is  evi- 
dently equal  to  one-half  its  departure  H  B.  The  longitude 
/  K  of  the  second  course  B  C  '\'&  equal  to  J  L  -\-  L  M  -\-  M  K 
equal  to  the  longitude  of  the  first  course  plus  half  the  de- 
parture of  the  first  course  plus  half  the  departure  of  the 
course  itself.  The  longitude  F^of  some  other  course  E  A, 
taken  anywhere,  is  equal  to  IV X  —  V X—  U  V,  or  equal 
to  the  longitude  of  the  preceding  course  minus  half  the  de- 
parture of  that  course  minus  half  the  departure  of  the  course 
itself,  i.  e.,  equal  to  the  algebraic  sum  of  these  three  parts, 
remembering  that  south  latitudes  and  west  longitudes  are 
negative,  and,  therefore,  to  be  subtracted  when  the 
instructions  are  to  make  an  algebraic  addition. 

To  avoid  fractions,  the  preceding  expressions  are  doubled, 
whence  we  deduce  the  following 

Rule  for  Double  Longitudes  : 

The  double  longitude  of  the  first  course  is  equal  to  its 
departure. 

The  double  longitude  of  the  second  course  is  equal  to  the 
double  longitude  of  t lie  first  course  plus  the  departure  of  that 
course  plus  the  departure  of  the  second  course. 

The  double  longitude  of  the  third  course  is  equal  to  the 
double  longitude  of  the  second  course  plus  the  departure  of 
that  course  plus  the  departure  of  the  course  itself. 

The  double  longitude  of  any  course  is  equal  to  the  double 
longitude  of  the  prcccditig  course  plus  the  departure  of  that 
course  plus  the  departure  of  the  course  itself. 

The  double  longitude  of  the  last  course  {as  well  as  of  the 
first)  is  equal  to  its  departure.  This  result,  when  obtained  by 
the  above  rule,  proves  the  accuracy  of  the  calculation  of  the 
double  longitudes  of  all  the  preceding  courses. 


LAND    SURVEYING. 


727 


Fig.  323. 


it  is  equal  to  the  product 


1 336.  Areas. — The  following  is  an  application  of  the 
rule  for  finding  areas  by  double  longitudes.  See  Fig.  323. 
Let  A  B  Ch&  2l  three-sided  field, 
of  which  A  is  the  most  westerly- 
station.  Through  A  draw  a 
meridian,  and  from  the  stations 
B  and  C  and  the  middle  points 
of  the  three  sides  of  the  field 
draw  perpendiculars  to  the 
meridian.  It  is  evident  that  the 
area  of  the  field  A  B  C  is  equal 
to  the  area  of  the  trapezoid 
D  B  C  E  less  the  triangles 
A  D  B  zxi6.A  E  C.  The  area  of 
the  triangle  A  D  B  \s  equal  to 
the  product  oi  A  Dhy  F  G,  i.  e. 
of  the  latitude  of  the  first  course  by  its  longitude.  The  area 
of  the  trapezoid  D  B  C  E  is  equal  to  the  product  oi  D  E  hy 
half  the  sum  oi  D  B  and  E  C,  or  H  K,  i.  e.,  it  is  equal  to  the 
product  of  the  latitude  of  the  second  course  by  its  longitude. 
The  area  of  the  triangle  A  E  C  is  equal  to  the  product  oi  A  E 
by  half  E  C,  ov  L  M,  i.  e. ,  it  is  equal  to  the  product  of  the 
latitude  of  the  third  course  by  its  longitude.  The  bearing 
of  the  course  A  Bis^  E,  and  that  of  C^i  is  N  W.  Their 
latitudes  are,  therefore,  north.  The  bearing  of  the  course 
.5  C  is  S  E,  and  its  latitude  is  south.  Calling  the  products 
in  which  the  latitude  is  north,  north  products,  and  the 
products  in  which  the  latitude  is  south,  south  products,  we 
find  the  area  of  the  trapezoid  to  be  a  south  product  and  the 
areas  of  the  triangles  to  be  north  products.  The  difference 
of  the  north  products  and  the  south  prodifcts  is,  therefore, 
the  area  of  the  three-sided  field  ABC. 

Using  double  longitudes,  to  avoid  fractions,  in  each  of 
the  preceding  products,  their  difference  will  be  double  the 
area  of  the  field  ABC. 

Take,  now,  a  four-sided  field,  A  B  C  D,  Fig.  324,  and 
drawing  a  meridian  through  its  most  westerly  station  A, 


728 


LAND    SURVEYING. 


and  longitudes  as  in  the  preceding  case,  it  will  be  evident 
from  inspection  that  the  area  of  the  field  A  B  C  D  is  equal 
to  the  trapezoid  F  C  D  G,  diminished  by  the  area  of  tri- 
angles A  G  D,  A  E  B,  and 
the  trapezoid  E  B  C  F. 
The  area  of  the  triangle 
A  E  B  is  equal  to  the 
product  of  the  latitude 
A  E  of  the  first  course  by 
its  longitude  H  K.  Its 
product  is  north.  The  area 
of  the  trapezoid  E  B  C  F 
is  equal  to  the  product  of 
the  latitude  E  F  of  the 
second  course  by  its  longi- 
tude L  M,  and  is  also  :i 
north  product.  The  area 
of  the  trapezoid  F  C  D  G 
is  equal  to  the  product  of 
the  latitude  F  G  oi  the 
third  course  by  its  longi- 
tude N  (9,  a  south  product. 
The  area  of  the  triangle 
A  G  D'\s  equal  to  the  prod- 
uct of  the  latitude  A  G  oi  the  fourth  course  by  its  longi- 
tude P  Q,  a  north  product.  Subtracting  the  sum  of  the 
north  products  from  the  sum  of  the  south  products  the 
difference  is  the  area  of  the  field  A  B  C  D.  If  double  longi- 
tudes had  been  used,  as  in  the  previous  case,  the  difference 
would  have  been  double  the  area  of  the  field. 


Fig.  324 


1337.  The  Application  of  I>oul>le  Longitudes  to 
the  FindinK  of  Areas. — Whatever  the  number  or  direc- 
tions of  the  sides  of  a  field  or  any  surface  enclosed  by 
straight  lines,  its  area  will  always  be  equal  to  half  the  dif- 
ference of  the  north  and  south  products  arising  from  multi- 
plying together  the  latitude  and  double  longitude  of  each 
course  or  side,  whence  the  following 


LAND    SURVEYING.  '        729 

General  Rule  for  Finding  Areas : 

1.  Prepare  ten  columns,  headed  as  in  the  following  exam- 
ples, and  in  the  first  three  write  the  stations,  bearings, 
and  distances. 

2.  Find  the  latitudes  and  departures  of  each  course  by  the 
traverse  table,  as  directed  in  A  rt.  1329,  placing  them  in  the 
four  following  columns. 

3.  Balance  them  as  in  Art.  1331,  correcting  them  in  red 
ink. 

If.  Fifid  the  double  longitudes  as  in  Art.  1335,  zvitJi  refer- 
ence to  a  meridian  passing  through  the  extreme  east  or  west 
station,  and  place  them  in  the  eighth  column. 

5.  Multiply  the  double  longitude  of  each  course  by  the 
corrected  latitude  of  that  course,  placing  the  north  prod- 
ucts in  the  nintli  column  and  the  south  products  in  the  tenth 
column. 

6.  Add  the  last  two  columns ;  subtract  the  smaller  sum 
from  the  larger,  and  divide  the  difference  by  two.  The 
quotient  will  be  the  content  required. 

1338.  To  Find  the  Most  Easterly  or  Westerly 
Station  of  a  Survey. — Make  a  rough  hand  sketch  of  the 
tract,  giving  the  sides,  their  approximately  true  direction,  and 
length.  The  most  easterly  or  westerly  station  may  then  be 
determined  from  an  inspection  of  the  sketch. 

Example  1  of  this  article  refers  to  the  five-sided  field,  a 
plat  of  which  is  given  in  Fig.  321,  and  the  latitudes  and  de- 
partures of  which  were  calculated  in  Art.  1330.  Station 
1  is  the  most  westerly  in  the  plat,  and  the  meridian  will  be 
passed  through  it. 

The  double  longitudes  are  found  by  applying  the  rule  for 
double  longitudes,  given  in  Art.  1335.  As  the  additions 
are  made  algebraically,  due  attention  must  be  paid  to  the 
signs.  The  double  longitudes  are  marked  D.  L.,  as  shown  in 
the  marginal  diagram.  These  double  longitudes  are  ob- 
tained by  the  following  operation.  As  stated  in- the  rule, 
the   double    longitude    of    the    first  course  is  equal  to  the 


730 


LAND   SURVEYING. 


stations. 

D.  L. 

1 

+  1.54D.L. 
+  1.54 
+  1.28 

2 

+  4.36D.L. 

+  1.28 
+  1.84 

3 

+  7.48D.L. 
+  1.84 
-1.99 

4 

+  7.33D.L. 

-1.99 

-2.67 

5 

+  2.67D.L. 

departure.  By  reference  to  the  given  example,  we  find 
that  the  departure  of  the  first  course  is 
1.54  chains,  an  cast  departure,  and,  there- 
fore, positive.  We  record  this  in  the 
column  headed  D.  L.,  opposite  Station  1. 
The  D.  L.  of  the  second  course  is  equal 
to  the  D.  L.  of  the  first  course  plus  the 
departure  of  that  course  plus  the  de- 
parture of  the  second  course.  Accord- 
ingly, we  place  under  the  D.  L.  of  the 
first  course,  the  departure  of  that  course, 
viz.,  +  1.54,  and  the  departure  of  the 
second  course,  viz.,  +  1-28,  as  given  in 
the  east  departure  column  of  the  exam- 
ple. This  sum,  viz.,  -|-4.36  is  the  D.  L. 
of  the  second  course  and  placed  opposite 
Station  2.  The  D.  L.  of  the  third  course 
is  equal  to  the  D.  L.  of  the  second  course 
plus  the  departure  of  that  course  plus  the  departure  of 
the  third  course.  Accordingly,  we  place  under  the  D.  L. 
of  the  second  course  the  departure  of  that  course, 
viz.,  +  1.28,  and  the  departure  of  the  third  course,  viz., 
+  1.84.  This  sum,  +  7.48,  is  the  D.  L.  of  the  third  course, 
which  we  place  opposite  Station  3.  In  a  similar  manner 
we  find  the  D.  L.  for  the  fourth  and  fifth  courses.  The 
double  longitude  of  the  last  course  is  equal  to  its  de- 
parture, which  proves  the  work.  The  double  longitudes  of 
the  courses  are  then  multiplied  by  their  corresponding  lati- 
tudes, and  the  content  of  the  field  obtained  as  directed  in 
the  given  rule. 

Had  the  meridian  been  supposed  to  pass  through  Station 
Jt,  the  most  easterly  station,  all  the  longitudes  would  have 
been  west  or  minus,  but  the  difference  in  the  double  areas 
would  have  been  the  same,  giving  the  same  content  as 
before. 

The  following  examples  will  give  the  student  some  prac- 
tice in  the  use  of  traverse  tables,  and  in  applying  latitudes 
and  departures  in  the  calculation  of  areas: 


LAND    SURVEYING. 


731 


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LAND    SURVEYING. 


733 


The  notes  of  the  survey  given  in  Example  3 
by  total  latitudes  and  total 
departures  from  Station  1. 
A  plat  of  the  survey  is  given 
in  Fig.  325  and  the  total  lati- 
tudes and  departures  in  the 
accompanying  table.  From 
an  inspection  of  the  plat  it 
will  be  seen  that  Station  2  is 
the  most  easterly,  and  the 
double  longitudes  given  in 
Example  3  are  reckoned  from 
a  meridian  passing  through 
that  station. 


are  platted 


Total 

Total 

Stations. 

Latitudes 
from 

Departures 
from 

station  1 . 

station  1. 

1 

0.00 

0.00 

2 

-3.13 

"t-  4.85 

3 

-4.94 

+  3.52 

4 

-5.71 

+  2.89 

5 

-6.06 

+  1.91 

6 

-5.61 

+    .76 

■     7 

-4.39 

-1.06 

8 

-3.51 

-    .48 

9 

-2.66 

-1.76 

1 

-0.00 

0.00 

Fig.  325. 


TOWN    SITES    AND    SUBDIVISIONS. 

1339.     First  Considerations. — In   laying    out  town 

sites  the  consideration  of  first  importance  is  the  location  of 

the  streets  rather  than  the  greatest  number  of  lots  obtainable. 

The  custom  of  laying  out  town  sites  in  rectangular  lines, 


734  LAND    SURVEYING. 

without  reference  to  topographical  conditions,  prevails 
almost  universally  throughout  the  United  States.  This  is 
largely  owing  to  two  principal  causes,  viz.,  first,  the  sup- 
position that  the  rectangular  method  or  plan  will  yield  the 
greater  number  of  lots,  and,  hence,  the  greater  profit,  and, 
second,  the  haste  in  surveying,  platting,  and  placing  the 
property  on  the  market  does  not  admit  of  a  thorough  study 
of  the  ground. 

The  town  site  should  be  considered  as  a  whole,  the  loca- 
tion of  its  main  streets  and  thoroughfares  being  determined 
by  traffic  considerations  chiefly.  These  considerations  will 
necessarily  involve  the  questions  of  grades,  drainage,  and 
railway  communications.  Without  the  latter  there  is  small 
excuse  for  a  town.  Where  possible  a  main  avenue  should  be 
laid  Qut,  parallel  with  the  railroad,  leaving  one  tier  of  lots 
between  the  street  and  track.  This  avenue  may  then  be  used 
as  a  base  from  which  to  lay  out  the  adjoining  streets  and 
avenues,  which  may  be  parallel  with  and  at  right  angles  to 
it  if  the  surface  be  generally  level,  or  at  oblique  angles  if 
the  surface  be  rolling  or  hilly. 

1340.     Grades,     Drainage,    and      Topography. — 

Grades  and  drainage  should  be  so  arranged  that  surface 
water  will  tend  to  form  main  channels,  i.  e.,  the  surface 
water  of  several  streets  will  find  its  way  into  some  particular 
street  where  special  provision  can  be  made  for  its  control 
and  discharge. 

The  streets  in  the  residential  portion  of  the  town  should, 
so  far  as  possible,  conform  to  the  existing  topographical  con- 
ditions. This  will  greatly  reduce  the  cost  of  grading  the 
streets,  give  easy  grades,  and  so  promote  comfort  of  pedes- 
trians and  the  efficiency  of  teams.  There  is  no  loss  in  front- 
age from  the  employment  of  curves  instead  of  straight  lines, 
and  there  is  no  question  of  the  advantage  of  the  former 
from  an  artistic  standpoint. 

The  accompanying  plan,  Fig.  326,  is  made  to  meet  the 
following  conditions,  viz.,  two  lines  of  railroad,  a  main  line 
and  branch,  meet  at  the  junction  of  two  streams.     The  land 


LAND   SURVEYING. 


735 


bordering  on  the  smaller  stream,  which  is  followed  by  the 
branch  road,  rises  rapidly  from  the  stream,  reaching  a  height 
of  200  feet,  and  then  falls  gradually  until  an  elevation  of  50 
feet  above  the  stream  is  reached,  when  the  surface  remains 
generally  level.  The  land  bordering  the  larger  stream,  which 
is  followed  by  the  main  line  of  the  railroad,  rises  gradually 
until  a  height  of  50  feet  above  the  stream  is  reached,  beyond 
which  the  surface  is  generally  level. 


1 

^^Pj 

^ 

/ 

1 

i 

'  L 
■a  " 

if 

— 1» 
1 

I 

-l'^ 

90' 

t 

i 

1 

'230' 

• 

.._t_ 

Avert 

lOO' 

Fig.  326. 

That  part  of  the  given  surface  which  is  generally  level 
will  be  laid  out  in  rectangular  blocks.  The  unaided  eye  will 
readily  determine  whether  a  town  site  is  well  adapted  to 
rectangular  divisions.  If  it  is  so  adapted  the  order  of  survey 
will  be  as  follows: 

1341.  General  Directions  for  Preliminary  Sur- 
vey.— Run  a  line  enclosing  the  entire  area,  giving  location 
of  prominent  features,  such  as  railroads,  highways,  streams. 


736  LAND    SURVEYING. 

houses,  etc.,  and  accurately  plat  to  a  scale  of  200  feet  to  the 
inch.  For  cities,  avenues  are  made  100  feet  in  width  be- 
tween building  lines,  and  streets  60  feet,  the  avenues  being 
parallel  to  each  other  and  the  streets  at  right  angles  to  the 
avenues.  City  lots  usually  have  fronts  of  25  feet  and  depths 
of  125  feet.  Part  of  New  York  is  laid  out  in  blocks  of  200 
feet  by  800  feet,  the  200  feet  facing  the  avenues.  Lots  are  100 
feet  in  depth,  each  block  containing  64  lots.  Having  deter- 
mined the  dimensions  of  the  streets  and  blocks,  lay  out  the 
principal  base  line  so  that  it  will  form  the  center  line  of  a 
street  or  avenue  running  parallel  with  the  general  direction 
of  the  railroad,  providing  for  overhead  or  sub-crossings 
where  practicable.  If  crossings  must  be  at  grade,  the  fewer 
of  them  the  better.  Provide  easy  and  safe  access  to  railroad 
stations  and  freight  depots. 

Lay  out  the  plat  in  rectangular  blocks,  accurately  scaling 
all  dimensions.  Arrange  the  plan  so  as  to  interfere  as  little 
as  possible  with  existing  lines  of  travel,  at  the  same  time 
giving  due  regard  to  the  future  needs  of  an  increasing  popula- 
tion. If  the  ground  is  wooded  or  sight  obstructed  by  under- 
brush, but  one  additional  base  line  can  be  used.  It  should 
be  about  midway  between  the  extremities  of  the  principal 
base  line  and  at  right  angles  to  it.  If,  however,  the  ground 
is  open  with  nothing  to  interfere  with  long  sights,  two  base 
lines  should  be  laid  out,  one  at  either  extremity  of  the  main 
base  and  at  right  angles  to  it. 

1342.  Measurements. — All  measurements  should  be 
made  with  a  standard  steel  tape  and  plumb-bob  and  care- 
fully checked.  The  base  lines  especially  should  be  measured 
with  great  care,  as  the  correctness  of  all  the  subsequent 
measurements  depends  upon  the  degree  of  accuracy  with 
which  these  primary  lines  are  measured. 

1343.  Base  Lines  and  Subdivisions. — The  rect- 
angular method  of  surveying  town  sites  is  illustrated  in 
Fig.  327,  in  which  A  B  is  the  principal  base,  and  the  aux- 
iliary bases  A  D  and  B  C  are  laid  off  from  the  extremities 
of  A  B.     The  avenues  are  at  right  angles  to  A  B,  and  the 


LAND   SURVEYING.  737 

streets  parallel  to  A  B.     Avenue  A  is  parallel  to  the  railroad, 


90 

Ti  \V  \     W 

o— o— o * o-^o 

A      E  O      T 


Fig.  327. 


or 


from  which  it  is  separated  by  a  25-foot  alleyway  and  one 
tier  of  lots  125  feet  deep.     Avenues  are  100  feet  in  width, 


738  LAND    SURVEYING. 

streets  GO;  blocks  250  feet  by  GOO  feet,  fronting  250  feet  on 
the  avenues,  and  the  lots  are  25  feet  by  125  feet. 

The  initial  point  A  of  the  principal  base  A  B  is  the  center 
of  an  avenue,  and  should  be  fixed  by  a  plug  2'  X  2'  X  18' 
driven  flush  with  the  surface  of  the  ground  and  the  center 
marked  by  a  tack,  with  a  guard  stake  beside  it,  and  num- 
bered 0.  Drive  a  temporary  plug  at  X  to  be  used  as  a  fore- 
sight in  giving  the  direction  of  A  B.  Set  up  the  instru- 
ment at  A  and  sight  to  X,  frequently  checking  the  foresight. 
Measure  from  A  ox\.  A  B  b'd  feet,  and  drive  a  12'  plug,  care- 
fully centering  the  same.  This  point  marks  the  north  side 
of  Avenue  B.  Continue  measuring  on  the  line  A  B,  driving 
a  stake  at  each  hundred  feet,  marking  the  exact  measure- 
ment by  a  tack,  and  number  in  .regular  succession  from  A. 
At  G50  feet  from  A  set  a  12"  plug  with  tack  center,  marking 
the  south  side  of  Avenue  C\  50  feet  further,  at  Station  7, 
set  a  12"  plug  with  center.  This  point  will  be  in  the  center 
of  Avenue  C',  at  7  -j-  50  a  plug  with  center  is  set,  marking 
the  north  side  of  Avenue  C.  In  like  manner  locate  the 
center  and  sides  of  all  avenues  lying  between  A  and  X, 
always  checking  the  foresight  before  setting  tack  centers. 
At  B  set  a  plug  2'  X  2'  X  18".  At  each  station  remeasure 
the  last  100  feet, so  as  to  secure  accurate  results.  The  measure- 
ment of  the  main  base  line  A  B  being  completed,  take  a 
foresight  on  Jfand  turn  off  an  angle  of  90°,  setting  a  tem- 
porary plug  at  Y.  Mark  the  center  at  Fwith  a  pencil  point 
and  repeat  the  angle  five  times,  marking  a  center  at  V  for 
each  angular  measurement.  These  points  will  vary  slightly 
in  position,  though  two  of  them  may  fall  at  the  same  place. 
Take  the  mean  or  average  of  these  points,  and  mark  the 
point  with  a  tack.  Then,  commencing  at  A  measure  the 
line  A  V,  setting  stakes  at  each  100  feet,  as  in  A  B,  and 
set  hubs  on  the  side  lines  of  Avenue  A  and  at  centers  and 
side  lines  of  the  streets  parallel  to  it,  checking  the  foresight 
at  V  and  the  measurement  of  each  station  before  setting 
plug  centers.  On  this  line  the  measurements  will  be,  first 
50  feet,  next  250,  then  GO,  250,  GO,  etc.,  the  streets  being 
60  feet  and  the  blocks  250  feet  in  width.     At  D  set  a  plug 


LAND    SURVEYING.  739 

2'  X  3*  X  18",  In  a  similar  manner  locate  the  base  line  B  C 
and  the  street  centers  and  side  lines  on  B  C.  Then  set  up 
at  D,  which  is  a  permanent  point,  and  foresighting  to  C  set 
points  on  centers  and  sides  of  avenues  on  D  C.  Next  set 
up  at  £",  foresighting  to  F.  Provide  a  supply  of  plugs 
1"  X  1'  X  8'  and  measure  from  E,  50  feet  in  both  directions 
on  the  line  E  F,  and  mark  the  points  with  pins.  These 
points  will  be  on  the  north  and  south  lines  of  Avenue  B. 
On  either  side  of  these  pins  in  the  line  E  F,  and  about  two 
feet  from  them,  set  plugs,  leaving  two  inches  of  their  length 
above  the  surface  of  the  ground.  Center  these  plugs,  dri- 
ving tacks  half  their  length  into  each  one.  In  the  same 
manner  set  plugs  on  both  sides  of  each  street  line  as  indi- 
cated by  the  small  circles  in  the  figure.  In  this  example 
B  C  '\?>  2,800  feet  distant  from  A  D,  too  great  a  distance  for 
the  accurate  setting  of  plug  centers;  therefore,  the  measure- 
ments from  A  D  to  B  C  should  terminate  on  the  south  line 
of  Avenue  D.  In  the  same  manner  locate  plugs  on  the  lines 
G  H,  I  K,  L  M,  etc.  Having  set  all  plugs  between  the 
base  A  D  and  the  south  line  of  Avenue  Z?,  move  the  instru- 
ment to  F  and,  foresighting  to  E^  set  plugs  on  both  sides  of 
all  avenues  between  Avenue  /^and  Avenue  Z>,  including  the 
north  side  of  D.  In  like  manner  locate  plugs  on  H  G,  K  I, 
ML,  etc.  Move  the  instrument  to  the  point  U;  stretch 
pieces  of  cord  between  the  plugs  on  both  sides  of  the  line 
X  T;  foresight  to  T,  and  at  each  intersection  with  the  cord, 
as  at  V,  IV,  etc.,  drive  a  12"  plug,  and  center  with  a  tack. 
This  method  of  locating  street  corners  by  intersections  has 
the  advantage  of  bringing  all  corners  on  the  same  street  in 
perfect  line,  a  result  which  it  would  be  practically  impossible 
to  obtain  by  direct  measurement.  The  measurement  of  all 
angles  is  referred  to  the  base  lines  where  special  care  is 
taken  in  checking  them, 

1344.  Permanent  Monuments. — The  street  and 
avenue  centers  located  on  the  base  lines  should  always  be 
rendered  permanent  by  setting  stone  monuments  at  those 
points. 


MAPPING. 


INTRODUCTION. 

1345.  The  object  of  this  section  is  to  furnish  the  stu- 
dent thorough,  practical  instruction  in  mapping.  Having 
previously  mastered  the  section  on  Geometrical  Drawing, 
he  should  by  this  time  be  familiar  with  the  various  instru- 
ments employed  in  the  drafting  room,  and  be  accustomed 
to  their  use. 

All  the  principles  and  methods  here  described  are  fully  il- 
lustrated by  drawings,  which  comprise  six  plates,  found  at 
the  end  of  the  volume  on  Mechanical  Drawing.  These  plates 
the  student  will  be  required  to  draw,  and  the  degree  of  pro- 
ficiency, as  shown  by  his  work,  will  determine  his  standing. 
The  examples  given  in  the  plates  are  similar  to  those  met 
with  in  practical  field  and  office  work. 

1346.  A  map  is  a  series  of  lines  and  angles  so  com- 
bined as  to  represent  the  true  outlines,  proportions,  and 
character  of  any  required  surface. 

1347.  Lines  are  either  boundaries  or  divisions  of 
the  required  surface.  They  have  only  the  properties  of 
direction  and  length. 

DRAWING    THE  PLATES. 


PLATE,  TITLE:  PLATTING  ANGLES  I. 

1348.  This  plate  contains  six  angle  lines,  three  of  which 
are  comprised  by  Fig.  1  and  three  by  Fig.  2.  The  three 
lines  a,  b,  and  c,  under  Fig.  1,  will  be  drawn  to  a  scale  of  200 
feet  to  the  inch,  platting  the  angles  with  a  protractor,   the 


742 


MAPPING. 


NOTES  FOR  LINE  a. 


use  of  which  was  fully  explained  in  the  section  relating  to 
Geometrical  Drawing. 

The  student  will  plat  these  lines  according  to  the  follow- 
ing directions,  being  careful  to  give  to  each  line  approxi- 
mately the  same  position  it 
occupies  in  the  plate.  This 
statement  also  applies  to  all  the 
plates  which  are  to  be  drawn 
from  the  data  given  in  thjs 
section.  In  these  examples, 
distances  are  expressed  in  sta- 
tions of  100  feet  each,  as  in 
the  section  on  Surveying.  The 
direction  of  each  line  is  referred 
to  that  of  the  immediately  pre- 
ceding line,  which  line  is  pro- 
duced and  the  angle  recorded 
as  being  to  the  right  or  left  of 
that  line.  In  practical  office  work,  the  lines  produced  are 
drawn  lightly  in  pencil  and  erased  as  soon  as  the  angles 
are  laid  off.  In  the  lines  a  and  b,  Fig.  1,  the  lines  produced 
are  dotted  and  the  angles  written  in  dotted  arcs,  in  order 
that  the  student  may  clearly  and  fully  understand  the 
method.  The  dimensions  of  the  following  plates  and  the  di- 
rections for  drawing  the  border  lines  are  the  same  as  for  the 
plates  on  Geometrical  Drawing.  The  notes  for  line  a  in 
Fig.  1  are  as  shown. 


Stations. 

Angles. 

25  +  84 

End  of  Line. 

21  +  94 

L.  32°  35' 

15  +  53 

R.  44°  10' 

11  +  72 

L.  60°  30' 

5  +  25 

L.  25°  15' 

0 

1349.  The  starting  point  A  of  the  line  is  numbered  0. 
The  first  angle  turned  is  at  Sta.  5  +  25,  which  we  denote  by 
B.  Locating  the  starting  point  A  about  three-fourths  of  an 
inch  from  the  lower  and  left-hand  border  lines,  we  draw  a 
straight  line,  giving  it  the  same  direction  as  that  given  to  it 
in  the  engraving.  Scale  off  from  yi,  to  a  scale  of  200  feet  to 
the  inch,  the  first  course,  525  feet  in  length,  locating  the 
point  /)'.  Produce  A  B  to  C,  being  sure  to  make  B  C  a. 
little  greater  than  the  diameter  of  the  protractor.  At  Sta. 
5  +  25,  B,  an  angle  of  25°  15'  is  turned  to  the  left.     Now, 


MAPPING.  743 

placing  the  center  of  the  protractor  on  the  point  B,  with  the 
zero  point  on  the  line  B  C,  lay  off  the  angle  25''  15'  to  the 
left  of/)  C,  marking  the  point  of  angle  measurement  /?with 
a  needle  point.  Through  the  points  ^and  Z>draw  a  straight 
line.  The  angle  C  B  D  is  25°  15',  and  the  line  B  D  is  the 
direction  of  the  next  course.  The  second  angle,  00°  30',  is 
turned  to  the  left  at  Sta.  11  +  72.  The  length  of  the  second 
course  is  found  by  subtracting  525  from  1,172,  giving  a  dif- 
ference of  647  ft.  Produce  B  D  and  scale  off  the  second 
course  647  ft.,  locating  the  point  E2X  Sta.  11  +  72.  Produce 
B  Eto  F,  and  lay  off  to  the  left  oi  E  F  the  angle  60°  30',  lo- 
cating the  point  G.  Join  E  and  G.  The  angle /^£  6"  is 
60°  30',  and  the  line  ^  6^  is  the  direction  of  the  next 
course. 

The  third  angle  is  R.  44°  10',  and  is  turned  at  Sta.  15  +  53. 
The  length  of  the  third  course  is  found  by  subtracting  1,172 
from  1,553,  giving  a  difference  of  381  feet.  Produce  E  G 
and  scale  off  from  E  the  distance  381  ft.,  locating  the  point 
H  at  Sta.  15  +  53.  Produce  E  H  to  K,  and  to  the  right  of 
H  K  lay  off  the  given  angle  44°  10',  locating  the  point  L. 
The  line  joining  the  points  H  and  L  forms  with  //  A'an  angle 
of  44°  10',  and  gives  the  direction  of  the  next  course. 
The  next  angle  is  L.  32°  35',  and  is  turned  at  Sta.  21  +  94. 
The  length  of  the  course  is  found  by  subtracting  1,553  from 
2,194,  giving  a  difference  of  641  ft.  Produce  H  L  and  scale 
off  from  //  the  distance  641  ft.,  locating  the  point  M  at 
Sta.  21  4-  94.  Produce  H  M  to  N,  and  to  the  left  of  M  N 
lay  off  the  given  angle  32°  35',  locating  the  point  O. 
Draw  M  O.  The  angle  N  M  O  is  32°  35',  and  M  O  is 
in  the  direction  of  the  next  and  last  course  of  line  a^ 
whose  length  is  found  by  subtracting  2,194  from  2,584. 
The  difference  is  390  ft.  We  produce  the  line  M  O,  and 
from  M  scale  off  the  last  course  of  390  ft.,  locating  the 
point  P  at  Sta.  25  +  84,  At  each  angular  point  in  the 
line  an  arc  is  described,  giving  <he  measurement  of  the 
angle. 

The  student  will  in  a  similar  manner  plat  the  following 
notes  for  the  lines  b  and  c.  Fig.  1,  of  the  same  plate: 


744  MAPPING. 

NOTES  FOR  LINE  b.  NOTES  FOR  LINE  C 


Stations. 

Angles. 

23  +  10 

End  of  Line 

10  +  35 

R.  25°  10' 

12  +  82 

L.    15°  15' 

8  +  50 

L.   30°  40' 

4  +  40 

R.  15°  20' 

0 

Stations. 

Angles. 

28  +  60 

End  of  Line 

21  +  4G 

R.  34°  30' 

17  +  09 

R.  53°  28' 

11  +  9G 

L.  25°  10' 

5  +  33 

R.  21°  10' 

0 

Fig.  328. 


1  350.  To  Lay  Off  an  Angle  by  Chords.— This  is 
done  by  means  of  a  table  of  chords  in  which  the  lengths  of 

chords  for  all  angles 
from  0  to  90°  are 
given  in  terms  of  a 
radius  1.  A  radius 
of  any  convenient 
length  may  be  as- 
sumed, and  the  cor- 
responding chord  length  obtained  by  multiplying  the  length 
of  the  chord  given  in  terms  of  radius  1  by  the  length  of  the 
assumed  radius.  Thus,  let  it  be  required  to  lay  off  from  a 
given  line  an  angle  of  40°  10'  to  the  left.  Let  A  B, 
Fig.  328,  be  the  given  line.  Produce  A  B  to  C,  making 
B  C=  400  ft.,  the  length  of  the  assumed  radius. 

From  a  table  of  chords,  we  find  that  the  chord  of  an 
angle  of  40°  10'  in  terms  of  a  radius  1  is  .G8G8.  Multiplying 
this  chord  by  400  ft.,  the  length  of  the  assumed  radius,  we 
have  274.72  ft.,  the  length  of  the  required  chord.  From  B 
as  a  center,  with  a  radius  B  C  =  400  ft.,  describe  to  the  left 
of  B  C  the  indefinite  arc  JC  D,  being  sure  that  the  length 
of  CD  is  slightly  greater  than  the  length  of  the  required 
chord,  and  from  (T  as  a  center,  with  a  radius  of  274.72  ft., 
describe  an  arc  intersecting  the  arc  C  D  in  C.     Through 


MAPPING. 


745 


B  and  C  draw  a  straight  line.  The  angle  C  B  C  \% 
40°  10',  the  required  angle.  This  method  of  platting  angles 
is  more  accurate,  though  less  rapid,  than  platting  with  a 
protractor. 

Note. — The  table  of  chords  used  for  the  calculations  given  in  this 
Course  may  be  found  in  Trautwine's  Pocket  Book,  a  very  useful  book 
to  all  surveyors.  If  the  student  does  not  possess  a  copy,  he  may  easily 
find  the  required  chord  from  his  table  of  sines  by  multiplying  the  sine 

40=  10' 
of  half  the  given  angle  by  2.     Thus,  the  chord  of  40°  10'  =  3  sin  — ^ —  = 

2  sin  20"  05  =  2  x.  34339  = 
same  as  given  in  the  table. 


178  =  .6868,  using  but  four  places,  the 


NOTES  FOR  LINE  a. 


1351.  Fig.  2,  same  plate  as  above,  contains  three  ex- 
amples in  the  lines  a,  b,  and  c,  in  which  the  angles  are  laid 
off  by  chords.  The  notes  for  example  a  are  given  in  the 
accompanying  table. 

The  first  course  A  B  is  360  feet  in  length,  which  the  stu- 
dent will  draw  to  a  scale  of  200  feet  to  the  inch.  The  start- 
ing point  A  is  numbered  0, 
and  B,  the  end  of  the  first 
course,  3+60.  At  j5  an  angle 
of  30°  30'  is  laid  off  to  the 
right.  Produce  A  B  400  feet, 
which  we  assume  to  be  the 
length  of  the  radius  in  calcu- 
lating chord  lengths  for  lay- 
ing off  angles,  and  locate  the 
point  C.  Then,  from  B  as  a 
center,  with  a  radius  of  400 
feet,  describe  the  indefinite 
arc  C  C  on  the  right  side  of 
the  radius  B  C,  being  sure  that  the  arc  shall  contain  at  least 
30°  30'.  We  find  in  a  table  of  chords  that  the  chord  of 
30°  30' =.5261,  which,  multiplied  by  400  ft.,  the  length 
of  the  assumed  radius,  gives  210.44  ft.,  the  length  of  the 
required  chord.  From  C  as  a  center,  with  a  radius  of 
210.44  ft.,  describe  an  arc  intersecting  the  arc  C  C  in 
the  point  E.  A  line  joining  B  and  E  will  form  with  the 
radius    B   C   2in    angle    C  B  E  =  30°   30',     the    required 


Stations. 

Angles. 

25  +  80 

End  of  Line 

20+38 

L.   37°  20' 

15  +  18 

L.   31°  08' 

9  +  13 

R.  39°  26' 

3  +  60 

R.  30°  30' 

'  0 

746 


MAPPING. 


angle.  The  next  angle  R.  39°  20'  is  turned  at  Sta.  9  + 13, 
making  the  length  of  the  second  course  553  ft.  Denote 
Sta.  9+13  by  F.  Produce  B  F  400  ft.  to  G.  From 
F  Sis  a.  center,  with  a  radius  F  G  oi  400  ft.,  describe  to 
the  right  oi  F  G  the  indefinite  arc  G  G\  being  sure 
that  the  arc  shall  contain  at  least  39°  2G'.  The  chord  of 
39°  20'  to  a  radius  1  is  .0747,  which,  multiplied  by  400  ft., 
gives  209.88  ft.,  the  length  of  the  required  chord.  From  F 
as  a  center,  with  a  radius  of  209.88  ft.,  describe  an  arc  in- 
tersecting the  arc  G  G'  in  H.  A  line  joining  F  and  //  will 
form  with  the  radius  F  G  the  angle  G  F  N  =  39°  20',  the 
required  angle.     The  next  angle,  viz.;  L.  31°  08',  is  turned 


NOTES  FOR  LINE  b. 


NOTES  FOR  LINE  c. 


Stations. 

Angles. 

22  +  40 

End  of  Line. 

10  +  50 

L.  18°  20' 

8  +  60 

R.  25°  14' 

3  +  25 

R.    8°  10' 

0 

Stations. 

Angles. 

25  +  34 

End  of  Line. 

19  +  94 

L.  51°  22' 

14+81 

R.  21°  20' 

10+38 

R.  39°  18' 

4+13 

L.  64°  30' 

0 

at  Sta.  15  +  18,  making  the  length  of  the  third  course  005  ft. 
Call  Sta.  15  +  18,  A".  Produce  F  K  400  ft.  to  L.  From  K 
as  a  center,  with  a  radius  K  L  oi  400  ft.,  describe  to  the 
left  of  K  L  the  indefinite  arc  L  M.  The  chord  of  31°  08'  is 
.5307,  which,  multiplied  by  400  ft.,  gives  214.08  ft.,  the  length 
of  the  required  chord.  From  Z  as  a  center,  with  a  radius 
of  214.08  ft.,  describe  an  arc  intersecting  the  arc  L  M  in 
the  point  N.  Join  K  and  h\  forming  with  K  L  the  angle 
LK  N-  31°  08'.  The  next  angle,  viz.,  L.  37°  20',  is  turned 
at  Sta.  20+38,  making  the  length  of  the  fourth  course 
520  ft.  Call  Sta.  20  +  38,  O.  Produce  K  O  400  ft.  to  P. 
From  6>  as  a  center,  with  a  radius  O  P,  describe  the  indefi- 


MAPPING. 


747 


nite  arc  P  Q.  The  chord  of  37°  20'  is  .6401,  which,  multi- 
plied by  400  ft.,  gives  25G.04  ft.,  the  length  of  the  required 
chord.  From  P  as  a  center,  with  a  radius  of  256.04  ft., 
describe  an  arc  intersecting  the  arc  P  Q  \n  R.  Join  O  and  R, 
forming  with  O  P  the  angle  P  O  R  —  'iT  20'.  The  end  of 
the  line  5  is  at  Sta.  25  +  80,  making  the  length  of  the  last 
course  542  ft.  In  a  similar  manner,  plat  the  notes  for  lines 
b  and  c^  which  are  given  in  Art.  1353. 

1352.     To  Lay  Off  an  Angle  by  its  Bearing.— By 

this  method  of  laying  off  angles,  the  direction  of  each  line 
is  referred  to  the  magnetic  meridian,  which  maintains  a  con- 
stant direction,  being  a  north  and  south  line.  The  bearing 
of  a  line  is  the  angle  which  the  line  makes  with  the  magnetic 
meridian.     In  platting  a  land  or  railroad  survey,  a  pencil 


kE     rQ 


Fig.  329. 

line  giving  the  direction  of  the  magnetic  meridian  is  drawn 
through  each  station  at  which  a  bearing  is  taken. 

The  direction  of  the  meridian  may  be  given  by  means  of 
the  ordinary  T  square  and  triangles,  and  the  angles  laid 
off  either  by  a  protractor  or  by  tangents.  The  use  of  T 
square  and  triangles  in  laying  off  angles  by  bearings  is  illus- 
trated in  Fig.  329.  A  sheet  of  paper  is  fastened  to  a  draw- 
ing board.     It  is  well  known  that  if  the  head  of  the  T  square 


748  MAPPING. 

be  kept  firmly  pressed  against  the  side  of  the  drawing  board, 
as  shown  in  the  figure,  the  lines  drawn  along  the  straight 
edge  will  be  parallel;  hence,  the  lines  drawn  perpendicular 
to  this  straight  edge  by  means  of  the  triangles,  as  shown  in 
the  figure,  will  be  parallel. 

Either  the  parallels  drawn  along  the  straight  edge  of  the 
T  square  or  of  the  triangle  may  be  used  as  the  magnetic 
meridian,  though  the  latter  is  preferable,  as  it  brings  the 
north  end  of  the  meridian  at  the  top  of  the  map,  which  is 
its  proper  position. 

Let*  it  be  required  to  plat  a  line  having  a  bearing  of 
N  G0°  E.  As  in  Fig.  329,  a  point  A  is  assumed  as  the  station 
at  which  the  bearing  is  taken.  Through  the  point  A,  a  line 
A  B  \?,  drawn  perpendicular  to  the  straight  edge  of  the  T 
square.  This  line  will  represent  the  direction  of  the  mag- 
netic meridian.  As  the  bearing  is  east,  the  angle  of  60°  will 
be  to  the  right  of  A  B.  Place  a  protractor  with  its  center 
at  A  and  its  zero  point  in  the  line  A  B.  Lay  off  the  angle 
60°,  and  mark  the  point  of  measurement  C  with  a  needle 
point.  Draw  a  line  joining  the  starting  point  A  with  the 
point  of  angle  measurement  C.  The  line  A  C  will  then 
form  an  angle  of  60°.  with  the  meridian,  and  its  course  will 
be  N  60°  E.  From  the  notes  find  the  length  of  the  first 
course,  and  measure  on  the  line  A  C  to  some  convenient 
scale  the  length  of  that  course,  locating  the  point  D,  where 
the  next  bearing  N  30°  E  is  taken.  Slide  the  T  square 
upwards,  and  with  the  triangle  draw  through  D  another 
meridian  D  E.  From  Z?as  a  center  lay  off  from  the  right  of 
the  meridian  D  E  the  bearing  N  30°  E.  Let  F  mark  the 
measurement  of  this  angle.  The  line  joining  D  and  F  will 
have  a  bearing  of  N  30°  E. 


PLATE,  TITLE:  PLATTING  ANGLES  IL 
1353.  This  plate  contains  five  angle  lines,  the  angles  of 
the  three  lines  given  in  Fig.  1  being  platted  by  magnetic 
bearings,  and  those  in  Fig.  2  by  tangents.  In  Fig.  1,  line  «, 
the  distances  are  given  in  stations  of  100  feet  each ;  in  the 
lines /^  and  r,  the  distances  are  given  in  chains.     The  student 


MAPPING. 


749 


will  draw  line  a  to  a  scale  of  200  feet  to  the  inch,  and  lines  d 
and  r  to  a  scale  of  2  chains  to  the  inch.  The  notes  of  line 
a  are  given  below. 

Let  A  be  the  starting  point  of  the  line,  which  we  num- 
ber Station  0.  Let  the  arrow  iV S  give  the  direction  of  the 
magnetic  meridian.  Through 
A  draw  a  meridian  A  B  parallel 
to  NS.  The  bearing  of  the 
first  course  is  N  10°  15'  E. 
From  the  meridian  passing 
through  A  lay  off  this  bearing 
angle  with  a  protractor,  as 
directed  in  Art.  1352.  The 
first  course  is  375  ft.  Draw  a 
line  through  A  having  the 
given  bearing,  and  scale  the 
distance  375  ft.  This  will  bring 
us  to  Sta.  3  +  75,  which  we  de- 
note by  the  letter  C,  where  a 
bearing  of  N  60°  E  is  taken. 
The  end  of  this  course  is  at 
Sta.  6  +  90.  The  length  of  the 
second  course  will,  therefore,  be  the  difference  between 
6  +  90  and  3  +  75,  which  is  315  feet.  Through  C  draw  a 
meridian  C  D,  from  which  lay  off  the  bearing  angle  of  60° 
and  draw  a  line  marking  the  second  course.  Scaling  the 
distance  315  feet  we  reach  Sta.  6  +  90,  which  we  call  E. 
Here  a  bearing  N  83°  30'  E  is  taken.  Through  E  draw  a 
meridian  E  E,  and  from  it  lay  off  the  bearing  N  83°  30'  E. 
The  end  of  this  course  is  at  Sta.  10  +  40.  Its  length  will, 
therefore,  be  the  difference  between  10  +  40  and  6  +  90, 
which  is  350  ft. 

Scale  off  this  distance  from  E,  locating  Sta.  10  +  40, 
which  we  call  G.  The  bearing  at  6^  is  S  81°  20'  E. 
Through  G  draw  the  meridian  G  H.  As  the  bearing  is 
S  E,  the  meridian  will  fall  below  the  station,  from  which 
lay  off  the  bearing  S  81°  20'  E,  and  draw  a  line  in  the 
direction   of   this   course.     The   next    bearing   is  taken  at 


NOTES  FOR  LINE  a. 

Stations. 

Bearings. 

28  +  15 

End  of  line. 

23  +  55 

S  45°  00'  E 

18  +  92 

S  70°  45'  E 

14  +  20 

N  80°  30' E 

10  +  40 

S81°  20' E 

6  +  90 

N  83°  30'  E 

3  +  75 

N  60°  00'  E 

0 

N10°  15' E 

750 


MAPPING. 


Sta.  14  4-  20.  The  length  of  the  course  is,  therefore,  the 
difference  between  14  +  20  and  10  -f-  40,  which  is  380  ft. 
Call  Sta.  14  +20,  K.  Through  A' draw  the  meridian  K  L. 
The  bearing  here  is  N  80°  30'  E.  From  the  meridian  K  L, 
lay  off  this  bearing  and  draw  a  line  in  the  direction  of  the 
course.  In  a  similar  manner  locate  the  remaining  stations 
and  lay  off  the  remaining  bearings  of  the  line.  The  bearing 
of  each  course  should  be  distinctly  written  above  it,  the 
letters  reading  in  the  same  direction  in  which  the  line  is 
measured. 

The  notes  for  the  lines  b  and  c  are  as  follows: 

NOTES  FOR  LINE  b. 


Stations. 

Bearings. 

Distances. 

1 
2 
3 
4 
5 

N  40^°  E 
N  65i°  E 
S  75i°  E 
S  45i°  E 
S  20i°  W 

4.22  chains 
6.75  chains 
8.70  chains 
6.60  chains 
5.18  chains 

NOTES  FOR  LINE  c 


Stations. 

Bearings. 

Distances. 

1 
2 
3 
4 
5 

S  47°    E 
N  20^°  E 
S  80°    E 
S  20°    E 
N  65i°  E 

6.60  chains 
8.80  chains 
4.32  chains 
6.54  chains 
7.48  chains 

1354.  The  regular  100-foot  stationing  is  used  in  rail- 
road and  highway  surveying,  but  in  land  surveying  the 
lengths  of  the  courses  are  given  in  surveyors'  chains.  As 
the   fractional   parts   of   chains   are    given   decimally,    the 


MAPPING.  751 

length  of  each  course  is  readily  scaled  on  the  plat  with  a 
decimal  scale.  The  notes  of  line  b  are  platted  as  follows: 
The  starting  point  is  called  Sta.  1,  and  so  marked  on  the 
plat.  Call  Sta.  1,  A.  Through  A  draw  a  meridian  A  B, 
and  from  it  lay  off  the  first  bearing,  N  40^°  E.  The  first 
course  is  4.32  chains  in  length,  which  lay  off.  to  a  scale  of 
2  chains  to  the  inch,  locating  Sta.  2,  which  call  C.  Through 
C  draw  a  meridian  C  D,  and  lay  off  the  given  bearing 
N  65^°  E.  The  course  with  this  bearing  is  6.75  chains  in 
length,  which  scale  off,  locating  Sta.  3.  In  similar  manner 
plat  the  remainder  of  line  b,  and  also  line  c.  Mark  dis- 
tinctly each  course,  giving  its  direction  and  length,  being 
careful  that  the  figures  and  letters  shall  read  in  the  same 
direction  in  which  the  line  is  being  run. 

1355.     To  Lay  Off  an  Angle  by  its  Tangent.— In 

laying  off  an  angle  by  its  tangent,  the  line  from  which  the 
angle  is  turned  is  prolonged  to  a  distance  equal  to  the 
length  of  the  assumed  radius.  The  length  of  the  tangent 
of  the  given  angle  is  then  found  in  terms  of  the  assumed 
radius  and  the  tangent  platted.  A  line  joining  the  angular 
point  with  the  extremity  of  the  calculated  tangent  will  give 
the  direction  of  the  required  line,  which  is  then  measured  to 
the  given  scale. 

Let  A  B,  in   Fig.  330,  be  the  given   line,  from  which  an 
angle  of  30°  15'  is  to  be  laid  off  to  the  right  at  the  point  B. 

Produce  A  B  to  (7,  ma-       b     B^400' 

king BC=  400  feet,  the 

length   of  the  assumed 

radius.       The    tangent 

of  30°  15'  in  terms  of  a 

radius  1, is. 58318, which,  ^'^-  ^• 

multiplied  by  400  feet,  the  length  of  the  assumed  radius, 

gives  233.27  feet,  the  length  of  the  required  tangent.     At 

C  erect  a  perpendicular  to  B  C  233.27  feet  in  length,  equal 

to  the  calculated  tangent.     Denote  the  end  of  this  tangent 

by  C.     Join  B  and    C.     The  angle  C  B  C  =  m°  15',  the 

given  angle,  and  the  line  B  C  is  the  required  line. 


752 


MAPPING. 


The  following  notes  which  are  platted  in  Plate,  Title: 
Platting  Angles  II,  Fig.  2,  the  student  will  plat  to  a  scale 
of  200  feet  to  the  inch : 


NOTES  FOR  LINE  a. 


Stations. 

Angles. 

Bearings. 

25  +  00 

19  +  97 

13  +  22 

5  +  00 

0 

End  of  Line 
L.  40°  10' 
R.  32°  15' 
R.  43°  30' 

N  78°  45'  E 
S61°05'E 
N  86°  40'  E 
N  43°  10'  E 

The  notes  for  line  a  are  platted  as  follows:  Having  ad- 
justed the  paper  to  the  drawing  board  and  drawn  a  merid- 
ian iV  5,  fix  the  starting  point  A,  which  number  0.  The 
first  course  is  500  feet  in  length,  which  plat  by  drawing  a 
meridian  A  B  through  Sta.  0,  and  scale  oflE  400  ft.  equal  to 
the  length  of  the  assumed  radius  A  C.  The  bearing  of 
the  first  course  is  N  43°  10'  E.  The  tangent  of  43°  10' 
is  .93797,  which,  multiplied  by  400,  the  length  of  the  radius, 
gives  375.19,  the  length  of  the  required  tangent.  Erect  a 
perpendicular  \.o  A  B  txX.  C,  and  on  this  perpendicular  scale 
off  to  the  right,  the  tangent  375.19  ft.,  calling  the  extremity 
of  the  tangent  D.  Draw  A  D.  The  angle  CAD  will 
be  43°  10'.  The  first  course  is  500  feet  in  length,  which 
scale  off  on  the  line  A  D  2it  200  ft.  to  the  inch,  locating  Sta. 
5  +  00  at  E.  The  angle  at  Sta.  5  +  00  is  43°  30'  to  the  right. 
Produce  A  E  and  scale  off  the  radius  E  7^=400  ft.  The 
tangent  of  43°  30'  =  .94896,  which,  multiplied  by  400,  gives 
379.58  ft.,  the  length  of  the  required  tangent.  Erect  a  per- 
pendicular to  E  F  at  F,  and  scale  off,  to  the  right,  the  tan- 
gent 379.58  ft.,  locating  the  point  G.  Draw  E  G.  The 
angle  F  E  G  '\s  43°  30',  and  the  line  E  G  the  required  line, 
the  bearing  of  which  is  N  80°  40'  E.  Produce  E  G  to  H, 
making  /:  //=  1,322  -  500  =  822  ft.  in  length. 


MAPPING. 


753 


The  line  changes  direction  again  at  Sta.  13  -f  22,  where 
an  angle  of  32°  15'  is  turned  to  the  right.  Denote  Sta. 
13  +  22  by  H.  Produce  E  H  400  feet,  equal  to  the  assumed 
radius,  calling  its  extremity  K.  The  tangent  of  32°  15'  = 
.63095,  which,  multiplied  by  400  feet,  gives  252.38  feet,  the 
length  of  the  required  tangent.  Erect  a  perpendicular  to 
H  K  2X  K  and  on  that  perpendicular  scale  off,  to  the  right, 
the  tangent  252.38  feet,  locating  the  point  L.  Join  H 
and  L.  The  angle  K  H  L  \s  32°  15'  and  the  bearing  oi  H  L 
is  S  61°  05'  E. 

The  line  changes  direction  again  at  Sta.  19  +  97.  Call 
this  station  AT.  The  angle  at  this  point  is  40°  10'  to  the  left. 
Produce  H  M  400'  to  yV,  and  at  N  erect  a  perpendicular 
to  M  N.  The  tangent  of  40°  10'  is  .84407,  which,  multiplied 
by  400,  gives  337.63  feet,  the  length  of  the  required  tangent. 
On  the  perpendicular  to  AT  N  sc2i\&  off,  to  the  left,  this  tan- 
gent, locating  the  point  O.  Join>/and  O.  The  end  of  the 
line  is  Sta.  25  +  00.  The  length  of  the  last  course  is  readily 
found  by  subtracting  19  +  97  from  25  +  00.  The  difference, 
503  feet,  is  scaled  off  on  M  O,  locating  the  point  P,  the  end 
of  the  line.  The  bearing  of  M  Pis  N  78°  45'  E.  In  a 
similar  manner  plat  the  notes  of  line  b. 

NOTES    FOR    LINE    b. 


Stations. 

Angles. 

Bearings. 

27  +  47 

End  of  Line 

20  +  97 

R. 

42° 

20' 

S34° 

25' 

E 

13  +  73 

R. 

49° 

10' 

S76° 

45' 

E 

7  +  63 

L. 

62° 

15' 

N54° 

05' 

E 

0. 

S  63° 

40' 

E 

1356.  To  Lay  Off  an  Angle  by  Latitude  and 
Departure. — The  subject  of  latitudes  and  departures  was 
discussed  in  the  section  on  Land  Surveying,  and  the  theory 
needs    no   explanation   in    connection    with    this    subject. 


754 


MAPPING. 


Suppose  the  bearing  of  a  line  is  N  40°  E,  and  its  length  is  300 
feet.     Its  latitude  and  departure  are  calculated  as  follows: 


Distances. 

Latitudes. 

Departures. 

3  0  0  ft. 

22  9  8 

19  2  8 

0  0  ft. 

0000 

0000 

Oft. 

0000 

0000 

3  0  0  ft. 

+  22  9.8  ft. 

+  192.8  ft. 

Departure  192.8' 


The  student  should  bear  in  mind  that  north  latitudes  and 
east  departures  are  +,  and  south 
latitudes  and  west  departures  are  — . 
^^  Let  A,  in  Fig.  331,  be  the  station 
at  which  the  bearing  is  taken. 
Through  A  draw  the  meridian  A^  S. 
From  A  upwards  scale  the  calculated 
latitude  229.8  ft.,  marking  the  ex- 
tremity B.  At  B  erect  a  perpen- 
dicular to  the  meridian  N  S,  draw- 
ing it  from  left  to  right,  as  the 
bearing  is  east.  On  this  perpen- 
dicular scale  off  the  calculated  de- 
parture 192.8  ft.,  locating  the  point 
C.     Join  A  and  C.     The  angle  BAC 

is  40°,  equal  to  the  given  bearing,  and  A  C  is  equal  to  the 

length  of  the  given  course,  viz.,  300  ft. 

Example. — Calculate  the  latitudes  and  departures  of  the  following 
courses,  and  plat  them  by  means  of  total  latitudes  and  total  departures 
from  Sta.  1. 


Fig.  331. 


Bearings. 

Distances. 

Latitudes. 

Departures. 

Stations. 

N  + 

S  - 

E  + 

W  - 

1 
2 
3 
4 

N  10i°  E 
N  41i"  E 
N  84i'  E 
S  25^"  E 

250  ft. 
123  ft. 
215  ft. 
210  ft. 

246  ft. 
91.76  ft. 
20.64  ft. 

189.94  ft. 

44.5  ft. 

81.92  ft. 

214.03  ft. 

89.57  ft. 

MAPPING. 


755 


Solution. — 

Distances. 
250  ft. 

200^  ft. 

50  ft. 

Oft. 


Latitndes. 

1968 
4920 
0000 


Departures. 

0356 
0890 
0000 


250  ft. 

246.000  ft. 

44.500  ft. 

123  ft. 

100  ft. 

2  0  ft. 

3  ft. 

0746 
1492 
2238 

0666 
1332 
1998 

1 2  3  ft. 

91.758  ft. 

81.918  ft. 

215  ft. 

200  ft. 

10  ft. 

5  ft. 

0192 
0096 
0479 

1991 
0995 

4977 

215  ft. 

2  0.63  9  ft. 

214.027  ft. 

2 1 0  ft. 

200  ft. 

10  ft. 
Oft. 

1809 
0904 
0000 

0853 
0427 
0000 

2 1 0  ft. 


189.940  ft. 


8  9.5  70  ft. 


Stations. 

Total  Latitudes  from 
Station  1. 

Total  Departures  from 
Station  1. 

1 
2 
8 
4 
5 

0.00  ft. 
+  246.00  ft. 
+  337.76  ft. 
+  358.40  ft. 
+  168.46  ft. 

0.00  ft. 
+    44.50  ft. 
+  126.42  ft. 
+  340.45  ft. 
+  430.02  ft. 

The  platting  of  the  courses  is  as  follows:  On  the  merid- 
ian A'^  6\  Fig.  332,  take  a  point  which  call  Sta.  1.  The  total 
latitude  of  Sta.  2  is  +  246  feet,  and,  as  it  is  a  plus  latitude, 
it  must  be  scaled  off  on  the  meridian  above  Sta.  1,  locating 


756 


MAPPING. 


the  points.  The  total  departure  of  Sta,  2  is  +44.5  feet. 
This  departure  will  therefore  be  to  the  right  of  the  merid- 
ian N  S.  At  A,  erect  a  perpendicular  to  the  meridian,  and 
upon  it  scale  off  the  total  latitude  44.5  feet,  locating  Sta.  2. 
The  line  joining  Stas.  1  and  2,  i.  e.,  the  first  course,  will 
have  a  bearing  of  N  10^°  E.  Its  length,  viz.,  250  feet,  we 
write  on  the  plat,  the  figures  reading  in  the  same  direction 
in  which  the  line  is  being  run. 

N 

k 


Total  Lat+368.4(f^ 
TotalLat+33r.76t 


Total  Lai.+246' 


TotalLat.+J68.46! 


Total  Dejk +340.45' 
^  Total  Dep^ 
B  +126.42^     /3 

Total  ^/V 
Dep. 

+■ 


Fig.  332. 


The  total  latitude  of  Sta.  3  is  +337.76  feet,  which  we  scale 
off  on  the  meridian  above  Sta.  1,  locating  the  point  B,  and 
on  a  perpendicular  to  the  meridian  at  B,  we  scale  off  the  total 
departure  of  Sta.  3,  which  is  +  120.42  feet,  locating  Sta.  3. 
The  line  joining  Stas.  2  and  3  has  a  bearing  of  N  41f°  E, 
and  length  of  123  feet.  The  total  latitude  of  Sta.  4  is 
+  358.4  feet,  which  we  scale  off  on  the  meridian  above  Sta.  1, 
locating  the  point  C,  where  we  erect  a  perpendicular  to  the 
meridian  and  upon  it  scale  off  the  total  departure  of  Sta.  4, 


MAPPING.  757 

viz.,  +  340.45  feet,  locating  Sta.  4.  The  line  joining  Stas.  3 
and  4  will  have  a  bearing  of  N  84^°  E,  and  a  length  of  215  feet. 
The  total  latitude  of  Sta.  5  is  +  1G8.46  feet,  which  we  scale 
off  on  the  meridian  locating  the  point  Z>,  where  we  erect  a 
perpendicular  to  the  meridian  and  upon  it  scale  off  the  total 
departure  of  Sta.  5,  viz.,  -j- 430. 02  ft.,  locating  that  point. 
The  line  joining  Stas.  4  and  5  has  a  bearing  of  S  25^°  E, 
and  a  length  of  210  ft.  This  method  of  platting  bearings  or 
angles  is  more  accurate  than  either  of  the  foregoing  methods, 
as  each  course  is  platted  independently.  Great  care  must, 
however,  be  observed  in  making  the  additions  by  which  total 
latitudes  and  departures  are  obtained.  Tables  of  latitudes 
and  departures  are  commonly  calculated  to  quarter  degrees. 
See  table  of  Latitudes  and  Departures.  Where  angles  are 
read  to  single  minutes,  a  table  of  sines  and  cosines  may  be 
used  to  advantage.  The  two  following  formulas  should  be 
memorized : 

Latitude  =  distance  X  cos  bearing.         (9^») 
Departure  =  distance  X  sin  bearing.  (98.) 

1357.  In  preliminary  railroad  work,  angles  are  com- 
monly platted  by  tangents,  but  on  difficult  parts  of  the  line 
where  all  dependence  must  be  placed  on  a  paper  location, 
latitudes  and  departures  should  be  used  and  the  line  platted 
to  a  scale  that  will  admit  of  full  topographical  details. 

For  practice  in  platting  lines  by  latitudes  and  departures, 
the  following  examples  are  given.  The  notes  of  Example  1 
are  platted  in  Fig.  333,  and  those  of  Example  2  are  platted 
in  Fig.  334. 

The  student  should  carefully  study  the  different  steps 
given  under  Art.  1356,  and  illustrated  in  Fig.  332,  before 
undertaking  to  plat  the  following  notes.  He  should  cal- 
culate the  latitudes  and  departures  for  each  course,  compa- 
ring his  results  with  those  given  in  the  text  and  likewise  with 
the  total  latitudes  and  departures  for  platting.  These  plats 
he  will  submit  for  inspection,  together  with  Plate,  Title: 
Platting  Angles  II. 


758 


MAPPING. 


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MAPPING. 


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MAPPING. 


A  piece  of  drawing  paper  one-half  the  size  of  an  ordinary 
drawing  plate  will  be  large  enough  to  contain  plats  of  both 
lines.  The  total  latitudes  and  departures  in  both  examples 
are  reckoned  from  Station  1,  which  in  Fig.  333  is  the  most 
westerly  station,  and  in  Fig.  334  the  most  easterly  one. 
Plat  the  courses  of  Example  1  to  a  scale  of  2  chains  to  the 
inch,  and  those  of  Example  2  to  a  scale  of  200  feet  to  the 
inch. 


N.89tK 


Fig.  888. 


In  Fig.  333,  a  magnetic  meridian  is  drawn  through  Sta.  1, 
which  we  call  A.  We  find  in  the  column  for  total  latitudes 
and  departures  from  Sta.  1  (see  Example  1),  that  the  total 
latitude  of  Sta.  2  is+  375.9  links,  which  we  scale  off  on  the 
meridian  above  ^  to  a  scale  of  2  chains  or  200  links  to  the 
inch,  locating  the  point  B.  The  total  departure  of  Sta.  2  is 
+  214.9  links,  which  we  scale  off  at  2  chains  to  the  inch  on  a 


MAPPING. 


761 


perpendicular  to  the  meridian  at  B,  locating  Sta.  2,  which  we 
call  C.  A  line  joining  A  and  6"  will  have  the  given  length 
and  bearing  of  the  first  course,  viz.,  length  4.33  chains,  and 
bearing  N  29|°  E. 

The  total  latitude  of  Sta.  3  is  -f-  461.2  links,  which  we  scale 
upon  the  meridian  above  A  at  2  chains  or  200  links  to  the 
inch,  locating  the  point  D.  The  total  departure  of  Sta.  3  is 
-\-  724.8  links,  which  we  scale  off  on  a  perpendicular  to  the 


SSf. 


Fig.  334. 

meridian  at  D,  locating  Sta.  3,  which  we  call  E.  A  line 
-joining  C  and  E  will  have  the  given  length  and  bearing  of 
the  second  course,  viz.,  length  5.17  chains,  and  bearing 
N  80^°  E.  In  a  similar  manner  plat  the  remaining  courses, 
bearing  in  mind  that  positive  latitudes  are  measured  on  the 
meridian  above  Sta.  1,  and  positive  departures  on  perpen- 
diculars to  the  right  of  the  meridian,  while  negative  latitudes 


762  MAPPING. 

are  measured  on  the  meridian  below  Sta.  1,  and  negative 
departures,  if  there  were  any,  on  perpendiculars  to  the  left 
of  the  meridian.  The  notes  for  Example  2  are  similarly 
platted,  excepting  that  the  meridian  passes  through  the 
most  easterly  station,  as  all  the  departures  from  Sta.  1  are 
negative.  The  lengths  of  the  courses  in  this  example  are 
given  in  feet,  and  are  to  be  platted  to  a  scale  of  200  feet  to 
the  inch.  Write  the  bearing  of  each  line  distinctly,  being 
careful  that  the  letters  read  in  the  same  direction  in  which 
the  line  is  run.  The  student  is  expected  to  accompany  each 
drawing  with  a  brief  description  of  the  successive  steps 
taken  in  the  work. 

1358.  Parallel  Rulers. — A  parallel  rule  is  a  straight 
edge  carried  on  milled  rollers  of  equal  diameter,  having  a 
common  axis.  They  are  of  great  service  in  drawing  meridian 
lines.  A  magnetic  meridian  is  drawn  the  entire  width  of 
the  sheet  which  is  to  contain  the  plat.  The  straight  edge 
of  the  rule  is  then  made  to  coincide  with  the  meridian  line 
and  then  rolled  across  the  paper  until  the  straight  edge 
passes  through  the  point  where  the  angle  is  to  be  measured. 
A  line  is  then  drawn  following  the  straight  edge ;  this  will 
be  a  meridian  line. 

1359.  The  Line  of  Survey. — The  line  of  prelim- 
inary  survey  is  a  succession  of  straight  lines  and  angles, 
or  an  angle  line,  as  it  is  commonly  called,  while  the 
located  line  is  a  succession  of  straight  lines  and  curves. 

1360.  Tangents  and  Curves. — Though  this  subject 
has  been  considered  in  the  section  on  Surveying,  yet  some 
additional  matter  may  be  of  advantage  in  connection  with 
the  subject  of  mapping. 

1361.  Map  of  Final  Location. — In  mapping  a  final 
location  the  measurements  should  be  made  from  inter- 
section point  to  intersection  pomt,  and  the  angles  platted 
either  by  tangents  or  by  latitudes  and  departures.  The 
points  of  curve  are  then  located  by  scaling  the  tangent 
distances  from  the  intersection  points.     The  curve  centers 


MAPPING. 


763 


o 


v^* 


FIG.  3.35. 


764 


MAPPING. 


are  best  determined  by  describing  intersecting  arcs  from 
the  tangent  points  as  centers,  with  radii  equal  to  that  of  the 
given  curve. 

Let   it   be  required   to  plat   by   tangents   the   following 
location  notes: 


Stations. 

Degree  of 
Curve. 

Intersection 
Angle. 

Tangent. 

Magnetic 
Bearing. 

25+50 
20+  10 
14+  55 
10  +  80 
0 

P.  T. 

P.  C.  5°  L. 

P.  T. 

P.  C.  6°  R. 

N     1°  00'  E 

27°  00' 

275.20  ft. 

N  28°  00'  E 

22°  30' 

190.03  ft. 

N    5°  30'  E 

The  tangent  distances  are  found  by  the  formula 

r=  Tetany/. 

(See  Art.  1251.)  The  first  curve  is  6°  R. ;  the  intersec- 
tion angle  /  is  22°  30'.  The  radius  of  a  6°  curve  is  955.37 
feet.  See  table  of  Radii  and  Chord  and  Tangent  Deflec- 
tions. 

i  7=11°  15'.  Tan  11°  15' =  .19891;  then  955.37  X 
.19891  ft.  =  190.03  ft.  =  T;  which  we  place  in  the  column 
headed  "tangent,"  opposite  the  intersection  angle  22°  30'. 
The  second  curve  is  5°  L;  the  intersection  angle  is  27°  00'. 
The  radius  of  a  5°  curve  is  1,146.28  feet.  ^  7=13°  30'. 
Tan  13°  30'  =  .24008,  and  1,146.28  ft.  X  .24008  =  275.2  ft.  = 
T,  which  we  place  in  tangent  column  opposite  the 
intersection  angle  27°  00'. 

A  plat  of  these  notes  is  given  in  Fig.  335.  The  order  of 
work  is  the  following:  First  we  select  a  starting  point  A, 
which  we  number  0,  and  through  this  point  draw  a  meridian 
A  B  with  its  north  point  at  the  top  of  the  plat. 

The  first  course  has  a  bearing  N  5°  30'  E.  From  Sta- 
tion 0,  scale  off  on  the  meridian  600  feet,  the  length  of  our 
radius  for  platting  angles.     The  bearmg  angle  is  5°  30'  and 


MAPPING.  765 

its  tangent  .09629,  which,  multiplied  by  600,  the  radius, 
gives  57.77  feet,  the  length  of  the  required  tangent.  Call 
the  extremity  of  the  radius  C.  At  C  erect  a  perpendicular 
to  A  B,  and  on  it  lay  off  the  tangent  57.77  feet,  locating  the 
point  D.  Join  A  and  D.  The  angle  C  A  D  =  5°  30'.  The 
P.  C.  of  the  first  curve  is  at  Station  10+  80.  The  tangent 
distance,  as  given  in  the  preceding  table,  is  190.03  feet. 
Hence,  the  distance  from  the  starting  point  to  the  first  in- 
tersection point  is  the  sum  of  1,080  and  190.03  feet,  which 
is  1,270.03  feet.  Produce  A  D,  making  a  total  distance  of 
1,270.03  feet  to  the  point  of  intersection  £,  and  600  feet 
additional  for  the  radius  by  which  the  next  angle  is  platted. 
Call  the  extremity  of  this  radius  F.  The  intersection  angle 
of  the  first  curve  is  22°  30'.  Its  tangent  is  .41421,  which, 
multiplied  by  600,  the  given  radius,  gives  248.52  feet  as  the 
required  tangent  for  platting  the  angle.  At  F  erect  a  per- 
pendicular to  the  radius  F  F  and  scale  off  the  tangent 
FG=  248.52  feet,  locating  the  point  G.  Join  F  and  G. 
The  angle  F  F  G  is  22°  30',  and  the  bearing  of  the  tangent 
F  G  is  "N  28°  E.  Next,  from  the  point  of  intersection  F, 
scale  off  on  the  lines  F  D  and  F  G  the  tangent  distance 
190.03  feet,  locating  the  P.  C.  at  H,  Station  10  +  80,  and 
the  P.  T.  at  K,  Station  14  +  55.  Now,  from  H  and  K  as 
centers  with  a  radius  955.37  feet  =  radius  of  6°  curve,  de- 
scribe arcs  intersecting  at  the  point  L.  Then,  from  Z,  as  a 
center  with  the  same  radius,  describe  a  curve  joining  the 
points  H  and  K.  The  curve  H  K  will  be  a  6°  curve  and 
will  be  tangent  to  the  lines  H  D  and  A'  G"  at  the  points  of 
curve  H  and  K.  The  next  intersection  point  M  is  in  the  line 
E  G  produced.  The  distance  between  these  intersection 
points  is  made  up  of  three  parts,  viz.,  the  tangent  of  pre- 
ceding curve,  which  we  know  to  be  190.03  feet;  the  inter- 
mediate tangent,  i.  e.,  the  distance  from  the  P.  T.  of  the 
first  curve  to  the  P.  C.  of  the  second  curve,  and  the  tangent 
of  the  next  curve  following.  The  P.  T.  of  the  first  curve  is 
at  Station  14  +  55;  the  P.  C.  of  the  second  curve  is  at 
Station  20+10;  the  intermediate  tangent  is,  therefore,  the 
difference  between  14  +  55  and  20  +  10,  which  is  555  feet. 


766  MAPPING. 

The  tangent  of  the  second  curve  is  275.2  feet.  Hence, 
the  distance  from  the  intersection  point  E  of  the  first  curve 
to  the  intersection  point  M  of  the  second  curve  is  the  sum 
of  190.03,  555,  and  275. 2  ft.,  which  is  1,020.23  ft.  Produce 
E  G  so  as  to  contain  1,020.23  ft.,  and  600  additional  feet  for 
a  radius,  the  extremity  of  which  call  N.  The  intersection 
angle  of  the  second  course  is  27°  00'  L.,  tan  27°  =  .50953. 
Radius  600ft.  X  .50953  =  305.72  ft.,  the  length  of  the  re- 
quired tangent.  Accordingly,  at  A''  we  erect  a  perpendicular 
to  the  radius  M  N^  and  on  that  perpendicular,  scale  off  the 
tangent  305.72  feet,  locating  the  point  O.  Join  3/ and  O. 
The  angle  N  M  O  \%  27°  00',  equal  to  the  given  intersection 
angle,  and  the  bearing  of  the  tangent  yl/  (9  is  N  1°  E. 
From  M  on  the  lines  M  K  and  M  O  scale  off  the  tangent 
distance  275.20  feet,  locating  the  P.  C.  at  P,  Sta.  20+10, 
and  the  P.  T.  at  (2,  Sta.  25  +  50.  Then,  from  P  and  Q  as 
centers  with  radii  of  1,146.28  feet,  the  radius  of  a  5°  curve, 
describe  arcs  intersecting  at  R.  From  /?  as  a  center  with 
the  same  radius  describe  the  curve  P  Q,  which  is  a  5°  curve, 
and  is  tangent  to  the  lines  Af  K  and  M  O  2it  P  and  Q. 
Write  the  bearing  of  each  tangent  in  its  proper  place,  being 
careful  that  the  bearings  shall  read  in  the  same  direction  in 
which  the  line  is  being  run. 


PLATE,  TITLE:  MAP  OF   RAILROAD  LOCATION. 

1362.  This  plate  contains  two  maps  of  railroad  loca- 
tion. Figs.  1  and  2,  the  notes  for  which  are  given  in  the  fol- 
lowing pages.  All  the  angles  are  laid  off  by  tangents  and 
the  notes  of  the  alinement  given  in  detail,  all  of  which  the 
student  must  carefully  go  over  and  check. 

The  student,  before  commencing  these  drawings,  should 
first  note  that  the  magnetic  meridian  (by  means  of  which 
the  direction  of  the  first  tangent  of  each  line  is  determined) 
is  parallel  to  the  right  and  left  border  lines  of  the  plate. 
He  must  also  determine  by  measurement  from  the  border 
lines    the    location  of   the  starting   point   0  of   each   line 


MAPPING.  767 

Without  these  precautions,  the  lines  are  liable  to  run  off  the 
paper,  necessitating  a  repetition  of  the  work,  and  involving 
the  erasure  of  lines,  which  always  soils  the  paper  and  mars 
the  appearance  of  the  drawing. 

He  will  make  the  drawing  to  a  scale  of  300  feet  to  the 
inch.  If  his  scale  reads  only  200  feet  to  the  inch,  he  will 
reduce  the  distances  given  to  a  scale  of  300  feet  to  the  inch, 
to  their  equivalent  to  a  scale  of  200  feet  to  the  inch.  The 
process  of  reduction  is  simple  and  may  be  readily  understood 
from  the  following:  A  line  which  measures  300  feet  in 
length  to  a  scale  of  300  feet  to  the  inch  will  measure  but 
200  feet  to  a  scale  of  200  feet  to  the  inch.  Hence,  in  chang- 
ing a  scale  from  300  feet  to  200  feet  to  the  inch  the  distances 
and  dimensions  will  scale  but  f  of  the  original  distances  and 
dimensions. 

Example. — A  line  measures  963  feet  to  a  scale  of  300  feet  to  the 
inch.     What  will  it  measure  to  a  scale  of  200  feet  to  the  inch  ? 

Solution. — |  of  963  =  642,  i.e.,  to  a  scale  of  200  feet  to  the  inch,  the 
line  will  measure  642  feet. 

1 363.  The  order  of  platting  the  notes  is  as  follows :  First 
draw  a  meridian  as  indicated  by  the  arrow.  Next,  having 
located  the  starting  point  A,  Fig.  1,  which  is  numbered  0, 
draw  through  that  station  a  parallel  meridian  A  B.  We  find 
from  the  notes  that  the  direction  of  the  back  tangent  A  A' 
(which  we  will  consider  a  part  of  a  line  of  railroad  already  con- 
structed) is  due  north  and  south,  and  that  Sta.  0  is  the  P.  C. 
of  an  8°  R.  curve  with  a  central  or  intersection  angle  of 
63°  10'.  The  tangent  distance  we  find  by  the  formula 
T==  R  tan  \  /,  is  440.7  feet.  This  distance  we  scale  off  on 
the  meridian  above  the  point  ^  to  a  scale  of  300  ft.  to  the 
inch,  locating  the  point  C,  which  is  the  intersection  point  of 
the  back  and  forward  tangents. 

Next,  from  Con  the  same  meridian,  we  scale  off  the  radius 
C  D  oi  400  feet  for  laying  off  the  angle  of  the  first  curve. 
The  angle  of  this  curve  is  63°  10'.  The  tan  of  63°  10'  is 
1.97681.  The  radius  400  ft.  X  1.97681  =790.7  ft.,  the  length 
of  the  required  tangent.     At   D  erect  a  perpendicular  to 


7G8 

MAPPING. 
NOTES    FOR    FIG 

.     1. 

Station. 

Deflection. 

Total 
Angle. 

Magnetic 
Course. 

Calculated 
Course. 

40 

12°  00' 

6°  00' 

18°  00' 

12°  00' 

6°  00' 

P.  C.  12°  L. 

89 

38  +  00 

36°  00' 

37 

36 

35  +  00 

34 

33  +  04.9 
33 

10°  40.3'  P.  T. 
10°  30' 
7°  00' 
3°  30' 
7°  14.7' 
3°  44.7' 
0°  14.7' 
P.  C.  7°  R. 

35°  50' 

S  36°  30'  E 

S  36"  40'  E 

32 

31 

30 

14°  29.4' 

29 

28 

27  +  93 

24 

21 

20  +  54.9 
20 

10°  38.8'  P.  T. 
9°  00' 
6°  00' 
3°  00' 
11°  31.2' 
8°  31.2' 
5°  31.2' 
2°  31.2' 
P.  C.  6°  R. 

44°  20' 

S  72°  30'  E 

S  72°  30'  E 

19 

18 

17 

23°  02.4' 

16 

15 

14 

13+  16 

12 

11 

10 

9 

8 

7  +  89.6 

7 

15°  35'  P.  T. 

12°  00' 

8°  00' 

4°  00' 

16°  00' 

12°  00' 

8°  00' 

4°  00' 

P.  C.  8°  R. 

63°  10' 

N  68°  00'  E 

N  63°  10'  E 

6 

5 

i 

4 

82°  00' 

! 

3 

j 

2 

1 

1 

0 

North 

North 

MAPPING. 
NOTES  FOR  FIG.   1. 


769 


Remarks. 


June  28, 1894. 


Int.  Ang. 

=  72°  00' 

From  intersection  to  intersection. 

12°  curve,  L.    R. 

=  478.34  ft. 

Tan  preceding  curve  =     264.8  ft. 

T. 

=  347.5  ft. 

Tan  between  curves  =     195.1  ft. 

P.  C. 

Length  curve 

P.  C.  C. 

Def.  100  ft. 

Def.  1  ft. 

=  35  +  00 
=  600  ft. 
=  41  +  00 
=  6°  00' 
=  3.6' 

Tan  12°  curve              =     347.6  ft. 

Total,                      =     807.5  ft. 
tan  72°  00' =  3.07768 
400  ft.  X  3.07768  =  1,231.1  ft. 

Int.  Ang. 

=  35°  50' 

From  intersection  to  intersection. 

7°  curve,  R.     R. 

=  819.02  ft. 

Tan  preceding  curve  =     389.2  ft. 

T. 

=  264.8  ft. 

Tan  between  curves  =     738.1  ft. 

P.  C. 

=  27  +  93 

Tan  7°  curve               =     264.8  ft. 

Length  curve 
P.  T. 

=  511.9  ft. 
=  33  +  04.9 

Total,                      =1,392.1  ft. 

Def.  100  ft. 

=  3°  30' 

tan  35°  50'  =  .72211 

Def.  1  ft. 

=  2.1' 

400  ft.  X  .72211  =     288.8  ft. 

Int.  Ang. 

=  44°  20' 

From  intersection  to  intersection. 

6°  curve,  R.     R. 

=  955.37  ft. 

Tan  preceding  curve  =     440. 7  ft. 

T. 

=  389.2  ft. 

Tan  between  curves  =     526.4  ft. 

P.C. 

=  13+16 
=  738.9  ft. 

Tan  6°  curve                =     389.2  ft. 

Length  of  curve 

Total,                       =1,356.3  ft. 

P.  T. 

=  20  +  54.9 

tan  44°  20'  =  .977 

Def.  100  ft. 

=  3°  00' 

400  ft.  X  .977  =     390.8  ft. 

Def.  1  ft. 

=  1.8' 

Int.  Ang. 

=  63°  10' 

Radius  1  =  400  ft. 

8°  curve,  R.     R. 

=  716.78  ft. 

tan  63"  10'  =  1.97681 

T. 

=  440.7  ft. 

400  ft.  X  1.97681  =  790.7  ft. 

P.C. 

=  0 

Length  of  curve 

=  789.6  ft. 

P.  T. 

=  7  +  89.6 

Def.  100  ft. 

=  4°  00' 

Def.  1  ft. 

=  2.4' 

770 


MAPPING. 
NOTES    FOR    FIG.    2. 


Station. 

Deflection. 

Total 
Angle. 

Magnetic 
Course. 

Calculated 
Course. 

13  +  41.7 
13 

10°  15'  P.  T. 
9°  00' 
6°  00' 
3°  00' 
6°  00' 
3°  00' 
P.  C.  6°  R. 

32°  30' 

S  79°  00'  E 

S  79°  00'  E 

13 

11 

10  +  00 

12°  00' 

9 

8  +  00 

5 

3 

0 

S  46°  30'  E 

NOTES  FOR  FIG.   \— Continued. 


Station. 

Deflection. 

Total 
Angle. 

Magnetic 
Course. 

Calculated 
Course. 

69  +  10.1 

61  +  65.1 

61 

15°  40'  p.  T. 

12°  44.1' 

8°  14.1' 

3°  44.1' 

P.  C.  9°  R. 

End 
31°  20' 

of  Line. 
N  39°  45'  E 

N  39°  40'  E 

60 

59 

58  +  17 

55 

54 

53 

52 

51 

50  +  00 
49 

17°  30'  P.  T. 
14°  00' 
10°  80' 

7°  00'  . 

3°  30' 
14°  00' 
10°  30' 

7°  00' 

3°  80' 
18°  00'  P.  C.  C.  7°  L. 

63°  00' 

N  8°  15'  E 

N  8°  20'  E 

48 

47 

46 

45 

28°  00' 

44 

43 

42 

41  +  00 

72°  00' 

N  71"  15'  E 

N  71°  20'  E 

MAPPING. 
NOTES  FOR   FIG.   2. 


771 


Remarks. 


June  28, 1894. 


Int.  Ang.  =  32°  30' 
6°  curve.  L.     R.  =  955.37  ft. 
T.  =  278.5  ft. 
P.  C.  =  8  +  00 
Length  curve  =  541.7  ft. 
P.  T.  =13  +  41.7 
Def.  100  ft.  =  3°  00' 
Def.  1  ft.  =  1.8' 


Radius  1  =  400.0  ft. 
From  Sta.  0  to  P.  C.  =  800.0  ft. 
Tan  6"  curve  =     278.5  ft. 


Total  from  P. C. to  P.I.  =  1,078.5  ft. 
tan  32°  30'  =  .63707 
400ft.  X. 63707=     254.8ft. 


NOTES   FOR  FIG.    \— Continued. 


Remarks. 


June  28, 1894. 


Int.  Ang.  =  31°  20' 
curve,  R.     R.  =  637.27  ft. 
T.  =  178.7  ft. 
P.  C.  =  58  +  17 
Length  curve  =  348.1  ft. 
P.  T.  =  61  +  65.1 
Def.  100  ft.  =  4°  30' 
Def.  1  ft.  =  2.7' 


Int.  Ang.  =  63°  00' 
7°  curve,  L.     R.  =  819.02  ft. 
T.  =  501.9  ft. 
P.  C.  C.  =  41  +  00 
Length  curve  =  900  ft. 
P.  T.  =  50  +  00 


From  intersection  to  intersection. 
Tan  preceding  curve  =  501.9  ft. 
Tan  between  curves  =  817.0  ft. 
Tan  9°  curve  =     178.7  ft. 


Total,  =  1,497.6  ft. 

tan  31°  20'  =.60881 
400ft.  X. 60881  =     243.5  ft. 


From  intersection  to  intersection. 
Tan  preceding  curve  =  347.6  ft. 
Tan  between  curves  =  0.0  ft. 
Tan  7°  curve  =     501.9  ft. 


Total, 


=     849.5  ft. 
tan  63°  =  1.96261 
400  ft.  X  1.96261  =     785     ft. 


772 


MAPPING. 


NOTES  FOR  FIG.  ^—Continued. 


Station. 

Deflection. 

Total 
Angle. 

Magnetic 
Course. 

Calculated 
Course. 

57  +  40 
47  +  19 

47 

8°  46.3'  P.  T. 

8°  15' 

5°  30' 

2°  45' 

8°  13.7' 

5°  28.7' 

2°  43.7' 
14°01.7'P.C.C.  5°30'L. 
14°  00' 
10°  30' 

7°00' 

3°  30' 
11°  58.2' 

8°  28.2' 

4°  58.2' 

1°  28.2' 
P.  C.  7°  L. 

End 
34°  00' 

of  Line. 
N  ir  15'  E 

N  11°  20'  E 

46 

45 

44  +  00 

16°  27.4' 

43 

42 

41  +  00.8 
41 

52°  00' 

N  45°  15'  E 

N  45°  20'  E 

40 

•     39 

38 

37  +  00 

23°  56.4' 

36 

35 

84 

33  +  58 

32 

30  +  36.6 
30 

13°  27.8'  P.  T. 
12°  00' 
8°  00' 
4°  00' 
10°  37.2' 
6°  37.2' 
2°  37.2' 
P.  C.  8°  L. 

48°  10' 

S  82°  80'  E 

S  82°  40'  E 

29 

28 

27  +  00 

21°  14.4' 

26 

25 

24  +  34.5 

24 

23 

22  + 14.4 
22 

9°  39'  P.  T. 
9°  00' 
4°  30' 
12°  36' 
8°  06' 
3°  36' 

P.  C.  9°  L. 

44°  80' 

S  84°  20'  E 

S  84°  80  E 

21 

20  +  00 

25°  12' 

19 

18 

17  +  20 

17 

15 

MAPPING.  773 

NOTES  FOR  FIG.  2— Continued. 


Remarks. 


June  28,  1894. 


Int.  Ang.  =  34'  00' 
5°30',  L.     R.  =  1,042.14  ft. 
T.  =318.6  ft. 
P.  C.  C.  =  41  +  00.8 
Length  curve  =  618.2  ft. 
P.  T.  =  47  +  19 
Def.  100  ft.  =  2°  45' 
Def.  1  ft.  =  1.65' 


Int.  Ang.  =  52°  00' 
curve,  L.     R.  =  819.02  ft. 
T.  =  399.5  ft. 
P.  C.  =  33  +  58 
Length  curve  =  742.8  ft. 
P.  C.  C.  =  41  +  00.8 
Def.  100  ft.  =  3°  30' 
Def.  1  tt.  =  2.1' 


Int.  Ang. 

8°  curve,  L.  R. 

T.  : 

P.  C. 

Length  curve 

P.  T. 

Def.  100  ft. 

Def.  1  ft.  ; 


Int.  Ang. 

9°  curve,  R.  R. 

T. 

P.  C. 

Length  curve 

P.  T. 

Def.  100  ft. 

Def.  1  ft. 


:  48°  10' 

:  716.78  ft. 

:  320.4  ft. 
24  +  34.5 
602.1  ft. 

:  30  +  36.6 

:  4°  00' 
2.4' 


44°  30' 
637.27  ft. 
260.7  ft. 
17  +  20 
494.4  ft. 
22  +  14.4 
4°  30' 
3.7' 


From  intersection  to  intersection. 
Tan  preceding  curve  =  399.5  ft. 
Tah  between  curves  =     0.0  ft. 
Tan  5°  30'  curve  =  318.6  ft. 

Total,  =  718.Tft. 

tan  34°  00'  =  .67451 
400  ft.  X  .67451  =  269.8  ft. 


From  intersection  to  intersection. 
Tan  preceding  curve  =  320.4  ft. 
Tan  between  curves  =  321.4  ft. 
Tan  7°  curve  =     399.5  ft. 


Total, 


=  1,041.3  ft. 
tan  52°  00'  =  1.27994 
400  ft.  X  1.27994  =     512  ft. 


From  intersection  to  intersection. 
Tan  preceding  curve  =  260.7  ft. 
Tan  between  curves  =  220. 1  ft. 
Tan  8°  curve  =  320.4  ft. 


Total, 


=  801.2  ft. 
tan  48°  10' =  1.11713 
400  ft.  X  1.11713  =  446.8  ft. 


From  intersection  to  intersection. 
Tan  preceding  curve  =  278.5  ft. 
Tan  between  curves  =  378.3  ft. 
Tan  9°  curve  =260. 7  ft. 


Total, 


=  917.5  ft. 
tan  44°  30'  =  .98270 
400ft.  X. 98270  =  393.1  ft. 


774  MAPPING. 

A  B,  towards  the  right,  as  the  curve  is  to  the  right,  and 
upon  this  perpendicular  scale  oflf  the  calculated  tangent 
700.7  ft.,  locating  the  point  E.  A  line  joining  the  points 
C  and  ^  will  give  the  direction  of  the  forward  tangent.  On 
the  line  C  E,  scale  off  from  C  the  tangent  distance,  440.7  ft., 
locating  the  point  /',  which  is  the  P.  T.  of  the  first  curve. 
From  A  and  /"as  centers,  with  radii  of  716.78  ft.,  the  radius 
of  an  8°  curve,  describe  arcs  intersecting  at  G.  Then,  from 
G  as  a  center,  with  the  same  radius,  describe  a  curve  joining 
the  points  A  and  F.  The  curve  A  F\s  zn  8°  curve  and  tan- 
gent to  the  lines  A  A'  and  F £  a.t  the  points  A  and  F. 

We  find  from  the  notes  that  the  next  curve  is  6°  R.  Its 
P.  C.  is  at  Sta.  13  +  16,  and  its  central  angle  is  44°  20'.  We 
find  its  tangent  distance  is  389.2  ft.  We  next  calculate  the 
distance  from  the  intersection  point  of  the  first  curve  to  the 
intersection  point  of  the  second  curve.  The  distance  is  com- 
posed of  three  parts;  viz.,  the  tangent  of  the  preceding 
curve,  which  is  440.7  ft. ;  the  intermediate  tangent,  i.  e., 
from  the  P.  T.  of  the  preceding  curve  at  Sta.  7  +  89.6  to  the 
P.  C.  of  the  second  or  6°  curve  at  Sta.  13  +  16,  a  distance  of 
526.4  ft.,  and  the  tangent  of  the  6°  curve,  which  is  389.2  ft., 
making  a  total  distance  of  1,356.3  ft.  Produce  the  line  CE, 
and  scale  off  from  Con  that  line  a  total  distance  of  1,356.3  ft., 
locating  the  point  H,  which  is  the  intersection  point  of  the 
second  or  6°  curve.  Produce  C  H  400  ft.  to  A"  for  a  radius 
in  laying  off  the  central  angle,  44°  20'  R.,  of  the  second 
curve.  The  tangent  of  44°  20'  is  .977,  which,  multiplied  by 
400,  gives  390.8  ft.  At  A"  erect  a  perpendicular  to  H K,  and 
upon  it  scale  off  the  tangent  390.8  ft.,  locating  the  point  L. 
The  line  joining  //and  L  gives  the  direction  of  the  forward 
tangent  of  the  second  curve.  Next,  from  the  intersection 
point  H,  scale  off  on  both  back  and  forward  tangents  the 
tangent  distance  389.2  ft.,  locating  the  P.  C.  of  the  second 
curve  at  J/,  Sta.  13  +  16,  and  its  P.  T.  at  N,  Sta.  20  +  54.9. 
Next,  from  J/ and  A^as  centers,  with  a  radius  of  955.37  ft., 
the  radius  of  a  6°  curve,  describe  arcs  intersecting  at  O. 
Then,  from  (9  as  a  center,  with  the  same  radius,  describe  a 
curve  joining  the  points  M  and  A^.     The  curve  M  N  is  a  6° 


MAPPING.  775 

curve  and  tangent  to  the  lines  F  H  and  H  L  zX  the  points  of 
curve  M  and  N. 

The  student  will  draw  the  tangent  distances  and  the  radii 
and  tangents  for  laying  off  angles  in  dotted  lines,  as  they 
are  simply  construction  lines.  The  line  of  survey  he  will 
draw  in  a  full,  bold  line,  as  shown  in  the  plate.  The  inter- 
section points  and  the  points  of  curve  and  tangent  are 
marked  by  small  circles,  the  latter  being  more  fully  described 
by  their  station  numbers.  Dotted  radial  lines  are  drawn 
from  the  center  of  each  curve  to  its  P.  C.  and  P.  T.  On 
one  of  these  radial  lines  the  length  of  the  radius  of  the  curve 
is  written,  and  the  amount  of  the  central  angle  written  with- 
in the  radial  lines.  The  student  will  need  no  further  direc- 
tions to  enable  him  to  plat  the  balance  of  the  line  and  also 
the  notes  for  Example  2,  a  plat  of  which  is  given  in  Fig.   2. 

1364.  Office  Curves  and  Beam  Compass. — Office 
curves  are  curves  of  different  radii,  whose  principal  object 


10 
Scale  100  ft=' 1  in 
12' 


Pig.  836. 

is  to  enable  the  engineer  to  readily  select  a  curve  which 
shall  best  fit  the  ground  lying  between  tangents,  as  shown 
in  the  topographical  map.  They  are  commonly  made  of 
pasteboard,  each  piece  containing  arcs  of  two  different  radii, 
the  degrees  of  curvature  of  which,  together  with  the  scale  of 
each,  being  distinctly  written,  as  shown  in  Fig.  336.  A  10° 
curve  to  a  scale  of  100  feet  to  the  inch  will  serve  for  a  5° 
curve  to  a  scale  of  200  feet  to  the  inch,  or  a  2°  30'  curve  to 
a  scale  of  400  feet  to  the  inch.  In  the  same  way,  a  12° 
curve  to  a  scale  of  100  feet  to  the  inch  will  serve  for  a  6° 
curve  to  a  scale  of  200  feet  to  the  inch,  or  a  3°  curve  to  a 


776  MAPPING. 

scale  of  400  feet  to  the  inch.  Office  curves  are  applied 
directly  to  the  contour  map  upon  which  a  grade  line  has 
been  platted,  and  the  curves  fitted  to  ground  and  tangent. 
Compound  curves  are  as  readily  fitted  as  simple  curves.  A 
satisfactory  line  being  decided  upon,  the  tangent  distances 
are  calculated  and  the  curves  struck  with  a  compass. 

When  the  radius  is  of  considerable  length,  it  is  difficult  to 
describe  a  true  circle  with  the  ordinary  compass  and  length- 
ening bar. 

An  accurate  substitute  is  found  in  the  beam  compass, 
which  consists  of  two  upright  legs;  one  pointed  and  fixed 
at  the  center  of  the  circle;  the  other  leg  carrying  either 
pencil  or  pen,  with  which  the  circle  is  described.     Both  legs 

B 


o 


o 


p 


Fig.  ,337. 


are  clamped  to  a  horizontal  arm  called  a  beam,  which  is 
lengthened  or  shortened  to  suit  the  radius.  A  cut  of  a  beam 
compass  is  shown  in  Fig.  337.  A  B  is  the  beam,  to  which  is 
clamped  the  needle  point  at  C  and  the  pen  or  pencil  at  D. 
At  ^  is  a  milled-headed  screw,  which  gives  slow  movement 
to  the  pen  or  pencil  at  D  and  adjusts  it  to  the  required 
radius. 


TOPOGRAPHICAL  DRAWING. 
1365.  General  Definition. — Topographical 
drawing  consists  of  the  representation  of  the  different 
features  of  any  portion  of  the  earth's  surface.  The  different 
features  will  comprise  all  its  inequalities  of  surface,  such 
as  hills,  hollows,  streams,  lakes,  valleys,  and  plains;  the 
location  of  towns,  highways,  canals,  and  railroads.  Detailed 
topographical  maps  give  individual  dwellings,  boundaries  of 
fields,  their  owners,  the  charactei  of  the  vegetation,  etc. 


MAPPING. 


777 


1366.  Systems. — There  are  three  principal  systems  of 
representing  topographical  features,  viz. : 

1.  By  level  contours  or  horizontal  sections. 

2.  By  lines  of  greatest  slope  perpendicular  to  contours. 

3.  By  shades  from  vertical  light. 

1367.  Ridge  Lines  and  Valley  Lines.— Ridge 
lines  are  the  lines  which  divide  the  water  falling  upon  them 
and  from  which  it  passes  off  on  opposite  sides.  They  are 
the  lines  of  least  slope  when  looking  along  them  from  above 
downwards,  and  the  lines  of  greatest  slope  when  looking 
along  them  from  below  upwards.  They  can  be  readily 
determined  by  the  slope  level.  On  these  lines  are  found  the 
projecting  or  protruding  bends  of  the  contour  lines. 

Valley  lines  are  the  reverse  of  ridge  lines.  They  are 
indicated  by  the  water  courses  which  follow  or  occupy  them. 
They  are  the  lines  of  greatest  slope  when  looked  at  from 
above  and  of  least  slope  when  looked  at  from  below.  On 
these  lines  are  found  all  the  receding  or  reentering  points 
of  the  contour  lines. 

1368.  Forms  of  Ground. — It  will  be  found  from  a 
general  examination  of  any  surface  that  ground  exists  under 
one  of  the  five  following  conditions,  viz. : 

1.   Sloping  down  on  all  sides ^  i.  e.,  a  hill,  as  shown  in  Fig. 


Fig.  338. 


Fig.  839. 


338,  the  direction  in  which  water  would  flow  being  indicated 
by  the  arrows. 


778 


MAPPING. 


2.  Sloping  up  on  all  sides,  i.  e.,  a  hollow,  as  shown  in 
Fig.  339. 

3.  Sloping  dozvn  on  tJirce  sides,  i.  e.,  shoulder  or  prom- 
ontory; the  end  of  a  ridge  or  watershed  line,  as  shown  in 
Fig.  340. 


Fig.  340. 


Pig.  841. 


4.  Sloping  up  on  three  sides  and  down  on  one  side,  i.  e.,  a 
valley,  as  shown  in  Fig.  341. 

5.  Sloping   up   on   two    sides    and   down    on   two   sides, 

alternately,    called   a  saddle,   and 
shown  in  Fig.   342. 

1369.  Clear  and  Intelligi- 
ble Maps. — No  pains  should  be 
spared  in  making  maps  clear  and 
intelligible.  All  water  courses, 
whether  occupied  or  dry,  should 
be  accurately  sketched,  and  gaps 
should  be  left  in  the  contour  lines 
at  suitable  intervals,  with  the  eleva- 
tion of  the  contours  written  in  them.  Where  time  and  cost 
are  not  to  be  considered,  the  lower  sides  of  the  contours  may 
be  hatched  as  though  water  were  draining  off  them,  and  the 
valleys  and  low  places  tinted  with  a  light  shade  of  India  ink. 
Sometimes  the  spaces  between  the  contour  lines  are  tinted 
with  India  ink,  increasing  the  tint  as  the  depth  increases. 

Ground  under  water  is  commonly  so  represented.  Begin- 
ning at  low  water-line,  the  space  to  the  depth  of  G  feet  is 
covered  with  a  dark  shade  of  India  ink ;  from  0  feet  to  12  feet 


Fig.  342. 


MAPPING.  779 

with  a  lighter  shade ;  from  12  feet  to  18  feet  with  still  lighter, 
and  from  18  feet  to  24  feet  with  lightest  of  all.  Greater 
depths  are  marked  in  fathoms. 

1 370.     Uses  of  Contours  : 

1.  To  locate  roads. 

2.  To  obtain  vertical  sections — profiles. 

3.  To  calculate  excavation  and  embankment. 

In  both  railroad  and  highway  location,  the  contour  map 
is  used  in  platting  a  grade  line  to  which  the  final  location 
should  closely  approximate.  The  paper  location  is  then  made, 
conforming  as  closely  as  possible  to  the  grade  line  in  the 
contour  map,  and  from  that  location  a  final  profile  is  platted. 

When  the  contour  map  is  to  be  used  as  a  basis  for  the  cal- 
culation of  excavation  and  embankment,  a  hill  or  hollow  is 
conceived  to  be  divided  into  horizontal  sections.  The  areas 
of  the  upper  and  lower  bases  of  any  section  are  then  calcu- 
lated and  their  average  is  multiplied  by  the  altitude  of  the 
section,  which  gives  the  content  of  that  section. 


PLATE,  TITLE  :  CONTOURS  AND  SLOPES. 
1371.  This  plate  contains  three  examples  in  topograph- 
ical drawing.  Each  example  affords  practice  in  drawing 
shore  lines.  Fig.  1  is  an  example  under  the  first  system  in 
which  the  topography  is  represented  by  level  contours,  and 
affords  the  student  excellent  practice  in  contour  mapping. 
Figs.  2  and  3  are  examples  under  the  second  system  in  which 
topography  is  represented  by  lines  of  greatest  slope  or 
hatchings. 

First  System — By  Level  Contours. — In  Fig.  1  the 
situation  is  a  steep  hillside  bordering  upon  a  lake.  The  en- 
gineer before  commencing  the  field  work  should  examine  the 
ground  thoroughly  in  order  that  he  may  intelligently  choose 
a  method  of  work  well  suited  to  the  situation.  In  the  case 
in  hand,  the  surface  of  the  water  in  the  lake  is  adopted  as 
the  datum  plane. 


780  MAPPING. 

It  is  a  common  and  excellent  practice  to  divide  the  area  to 
be  contoured  into  squares,  the  dimensions  of  which  will  de- 
pend upon  the  area  to  be  treated  and  the  degree  of  detail 
required  in  the  work.  Large  areas  are  usually  divided- into 
squares  containing  100  ft.  on  a  side.  The  division  lines 
serve  as  guides  to  those  taking  the  levels.  The  intersections 
of  the  division  lines  being  100  ft.  apart,  they  render  the  loca- 
tion of  any  intermediate  point  an  easy  task.  These  inter- 
sections are  called  stations,  and  are  usually  numbered 
consecutively  or  distinguished  in  some  other  way.  In  Fig. 
1  the  area  is  divided  into  squares  100  ft.  on  a  side.  Base 
lines  A  X  and  A  H  are  first  established  where  distant  and 
well-defined  targets  may  be  set  up  and  the  lines  carefully  meas- 
ured. The  importance  of  an  accurately  measured  base  line, 
and  of  a  distant  fixed  target  can  not  be  overestimated.  The 
lines  of  division  are  determined  by  laying  off  lines  at  90°  to 
these  bases,  and  are  supposed  to  be  parallel,  a  difficult  thing 
to  accomplish  in  rough  country  where  short  sights  are  fre- 
quent, and  impossible  if  the  initial  angle  of  each  line  is  not 
turned  from  the  same  backsight,  and  that  a  comparatively 
distant  one.  The  base  lines  being  established,  the  lines  of 
division  are  carefully  run.  The  vertical  division  lines,  i.  e., 
those  parallel  to  general  direction  of  the  lake  shore,  are  des- 
ignated by  the  letters  of  the  alphabet,  the  first  being  de- 
scribed as  line  A^  the  next  as  line  B^  the  next  as  line  C,  and 
so  on.  The  horizontal  division  lines  are  numbered  consec- 
utively, commencing  with  the  bottom  line,  which  is  num- 
bered 0,  the  next  parallel  to  it  1,  the  next  2,  and  so  on. 
The  intersections  of  the  division  lines  locate  the  succeeding 
stations  on  each  line.  This  greatly  simplifies  the  keeping  of 
the  notes,  and  enables  the  engineer  to  readily  locate  any 
point  and  brieflly  describe  it.  Thus,  the  starting  point  of 
line  A  is  called  line  A^  0;  the  next  intersection  is  called  line 
A,  1;  the  next  line  A^  2,  etc.  The  engineer  determines  the 
form  of  notes  best  suited  to  the  situation.  He  will  find  a 
leveling  rod  20  ft.  in  length  of  great  assistance  when  work- 
ing in  a  locality  where  changes  in  elevation  are  frequent 
and  abrupt.     The  form  of  notes  best  adapted  to  the  work  in 


MAPPING. 


781 


hand  is  the  following,  the  notes  being  a  record  of  the  levels 
which  are  taken  at  each  intersection  of  the  division  lines: 

LEVELS  OF  LINE  A. 


Station. 

Rod  Reading. 

Height  of 
Instrument. 

Elevation. 

B.  M. 

+    8.80 

56.05 

47.25 

0 

7.20 

48.80 

1 

13.70 

42.30 

T.  P. 

-  19.72 

36.33 

+    4.20 

40.53 

2 

5.70 

34.80 

3 

14.80 

25.70 

T.  P. 

-  18.63 

21.90 

+    3.53 

25.43 

4 

7.10 

18.30 

5 

9.30 

16.10 

T.  P. 

-  18.55 

6.88 

+    3.22 

10.10 

6 

9.60 

0.50 

6  +  05 

Edge  of  Lake. 

1372.  The  contour  map  is  made  as  follows:  First 
we  draw  the  outlines  of  the  given  area,  1,100  ft.  in  length 
by  750  ft.  in  width,  to  a  scale  of  100  ft.  to  the  inch.  These 
boundaries  are  then  divided  into  equal  spaces  of  100  ft.  each, 
as  shown  in  the  engraving,  and  the  lines  of  division  drawn, 
the  boundaries  being  drawn  full  and  the  division  lines  dotted. 
The  vertical  division  lines,  as  before  stated,  are  designated 
by  the  letters  of  the  alphabet,  and  the  horizontal  lines  by 
numerals. 

From  the  level  notes  we  find  the  elevations  of  the  stations 
on  lines  A  and  B.  These  elevations  we  mark  on  the  map  at 
their  proper  stations,  and  then  locate  the  contour  lines  as 
follows:  Beginning  with  line  A,  we  find  that  the  elevation 
of  Station  0  is  48.8  ft.  ;  that  of  Station  1  is  42.3  ft.  ;  hence, 


782 


MAPPING. 


the  difference  of  elevation  between  these  stations  is  48.8  — 
42.3  =  6.5  ft.   The  distance  between  these  stations  is  100  ft., 

and  the  rate  of  fall  between  Stations  0  and  1  is  equal  to  ——  = 

0.5 

15.4,  which  is  called  a  descending  slope  of  1  to  15.4.  The 
contours  are  5  ft.  apart,  and,  therefore,  the  elevations  of 
each  contour  will  be  some  multiple  of  5  ft.  Contour  45  ft. 
will  come  between  Stations  0  and  1  of  line  A.  As  the  eleva- 
tion of  Station  0  is  48.8  ft.,  we  must,  to  reach  contour  45,  go 

LEVELS  OF  LINE  B. 


Station. 

Rod  Reading. 

Height  of 
Instrument. 

Elevation. 

10.10 

7  +  12 

Edge  of  Lake. 

7 

8.00 

2.10 

T.  P. 

-    1.24 

8.86 

+  19.84 

28.70 

6 

8.30 

.     20.40 

T.  P. 

-    1.65 

27.05 

+  19.91 

46.96 

5 

15.00 

32.00 

4 

9.20 

37.80 

3 

1.70 

45.30 

T.  P. 

-    2.21 

44.75 

+  18.88 

63.63 

2 

6.90 

56.70 

T.  P. 

-    2.24 

61.39 

+  18.31 

79.70 

1 

15.50 

64.20 

0 

4.40 

75.30 

towards  Station  1  far  ienough  to  descend  an  amount  equal 
to  48.8  —  45.0  =  3.8  ft.  As  the  rate  of  fall  is  1  in  15.4,  to 
fall  3.8  ft.  we  must  go  15.4  x  3.8  =  58.5  ft.,  which  brings  us 


MAPPING.  783 

to  contour  45.  This  distance  we  scale  off  to  a  scale  of 
100  ft.  to  the  inch,  marking  the  point  where  contour  45 
crosses  line  y^  by  a  small  dot.  The  next  two  lower  contours 
are  40  and  35.  As  the  elevation  of  Station  1  is  42.3  and  that 
of  Station  2  is  34.8,  both  of  these  contour  lines  will  cross  the 
line  between  these  stations.    The  total  fall  between  Stations 

1  and  2  is  42.3  -  34.8  =  7.5  ft.,  and  the  rate  of  fall  is  ^  = 

13.3.  To  reach  contour  40  we  must  fall  2.3  ft.  below  Station 
1,  and  the  distance  will  be  2.3  X  13.3  =  30.6  ft.  To  reach 
contour  35  we  must  fall  5  ft.  more,  and  the  additional  dis- 
tance will  be  5  X  13.3  =  66.5  ft.  We  accordingly  locate 
those  contours  at  30.6  ft.  and  at  30.6  +  66.5  =  97.1  ft.  from 
Station  1.  The  difference  of  elevation  between  Stations  2 
and  3  is  34.8  —  25.7  =  9.1  ft.,  and  equivalent  to  a  de- 
scending slope  of  1  to  11  between  them.  Contour  30  will 
come  at  4.8  X  11  =  52.8  ft.  from  Station  2.  The  difference 
of  elevation  between  Stations  3  and  4  is  25.7  —  18.3  =  7.4  ft., 
which  gives  a  descending  slope  of  say  1  to  14.  This  is  not 
the  exact  rate  of  slope,  but  where  decimal  fractions  are  small 
and  slopes  easy  the  fractions  may  be  ignored,  as  they  will  not 
to  a  perceptible  degree  affect  the  accuracy  of  the  work.  Con- 
tour 25  will  come  at  14  X  .7  =  9.8  ft.  from  Station  3,  and 
contour  20  at  a  point  70  ft.  farther,  or  at  say  80  ft.  from 
Station  3.  The  difference  of  elevation  between  Stations  4 
and  5  is  18.3  —  16.1  =  2.2,  but  no  contour  line  passes  between 
these  points.  The  difference  of  elevation  between  Stations 
5  and  6  is  16.1  —  .5  =  15.6,  which  gives  a  slope  of  1  to  6.4. 
This  brings  contour  15  at  7  ft.,  contour  10  at  39  ft.,  and 
contour  5  at  71  ft.  from  Station  5. 

1373.  The  usual  custom  is  to  -work  up  the  notes,  as  it  is 
called,  before  commencing  the  platting  of  the  contours, 
and  when  a  considerable  portion  of  the  ground  has  been 
covered,  plat  them,  and  thus  avoid  the  delay  incurred  by 
frequent  changes  of  work.  Each  engineer  decides  upon 
that  form  of  notes  best  suited  to  the  character  of  the  work 
in  hand.     The  following  is  a  clear  and  simple  form  of  notes 


784 


MAPPING. 


in  which  is  given  the  location  and  elevation  of  the  con- 
tours on  line  B  and  on  the  cross-section  lines  between  lines 
A  and  B: 


Line  B. 

Contours  Between  Lines 
A  and  B. 

Sta.  0  to  1. 

from  A  0  to  B  0. 

0  +  3  to  contour  75 

5  ft.  to  contour  50 

0  +  48  to  contour  70 

24  ft.  to  contour  55 

0  +  93  to  contour  65 

43  ft.  to  contour  60 

62  ft.  to  contour  65 

81  ft.  to  contour  70 

97  ft.  to  contour  75 

Sta.  1  to  2. 

A  1  to  B  L 

1  +  56  to  contour  60 

12  ft.  to  contour  45 

34  ft.  to  contour  50 

57  ft.  to  contour  55 

79  ft.  to  contour  60 

Sta.  2  to  3. 

A  2  to  B  2. 

2  -f- 15  to  contour  55 

1  ft.  to  contour  35 

2  +  59  to  contour  50 

23  ft.  to  contour  40 

46  ft.  to  contour  45 

68  ft.  to  contour  50 

91  ft.  to  contour  55 

Sta.  3  to  4. 

A  3  to  B  3. 

3  +  04  to  contour  45 

21  ft.  to  contour  30 

3  +  70  to  contour  40 

46  ft.  to  contour  35 

71  ft.  to  contour  40 

96  ft.  to  contour  45 

MAPPING. 


785 


Line  B. 

Contours  Between  Lines 
•   A  and  B. 

Sta.  4  to  5. 

A  ito  B  i. 

4+48  to  contour  35 

9  ft.  to  contour  20 

34  ft.  to  contour  25 

59  ft.  to  contour  30 

84  ft.  to  contour  35 

Sta.  5  to  6. 

A  5  to  B  d. 

6  +  17  to  contour  30 

24  ft.  to  contour  20 

5  +  60  to  contour  25 

55  ft.  to  contour  25 

86  ft.  to  contour  30 

Sta.  G  to  7. 

A  6  to  B  6. 

6  +  02  to  contour  20 

22  ft.  to  contour    5 

6  +  29  to  contour  15 

47  ft.  to  contour  10 

6  +  56  to  contour  10 

72  ft.  to  contour  15 

6  +  83  to  contour    5 

97  ft.  to  contour  20 

Sta.  7. 

^  7  to  B  7. 

7  +  12  to  contour  0, 

95  ft.  to  contour  0, 

at  edge  of  lake. 

at  edge  of  lake. 

1374.  The  student  having  worked  up  these  notes  can, 
with  a  little  practice,  plat  them  rapidly,  using  a  decimal 
scale.  A  small  offset  scale  is  very  convenient  in  locating 
contours.  The  examples  given  in  working  up  notes  will 
enable  the  student  to  similarly  treat  the  others.  He  should 
be  systematic  in  his  calculations  and  platting,  completing 
all  the  calculations  on  one  line  before  commencing  another, 
and  do  likewise  in  his  platting.  Otherwise,  confusion  is 
sure  to  follow. 


786  MAPPING. 

The  elevations  of  the  ground  at  the  intersections  of  the 
division  lines  are  given  in  the  engraving.  This  is  done  for 
the  convenience  and  assistance  of  the  student.  In  regular 
office  work  the  elevations  of  these  points  are  taken  from  the 
level  book,  and  the  only  elevations  given  in  the  map  are 
those  of  the  contours,  which  are  written  in  gaps  left  in  the 
contours  for  that  purpose. 

These  elevations  should  be  distinctly  written,  and,  unless 
the  slopes  are  very  steep,  bringing  the  contours  very  close 
together,  the  elevations  should  be  written  successively  one 
above  the  other.  In  drawing  the  shore  line,  avoid  the 
drawing  of  straight,  regular  lines.  All  shore  lines,  and 
especially  those  of  lakes,  are  very  irregular.  A  heavy  line 
is  first  drawn  outlining  the  shore,  then  a  lighter  one,  at  a 
small  distance  from,  and  parallel  to,  the  first;  then  another 
line,  at  a  greater  distance  from  the  second  than  the  second 
is  from  the  first ;  and  so  on  until  the  shore  line  is  clearly 
defined. 

The  contours  themselves  are  to  be  drawn  free-hand  with 
an  ordinary  writing  pen. 

1375.     Second    System — By    Lines    of    Greatest 

Slope. — Their  direction  is  that  which  water  would  take  in 
running  off  them.  They  are  drawn  perpendicular  to  the 
contour  lines^  and  are  called  hatchings.  An  example  of  this 
system  is  shown  in  Fig.  343. 

In  sketching  topography  by  this  system,  the  topographer 
should  hold  the  book  directly  in  front  of  him  so  as  to  corre- 
spond with  his  position  on  the  ground,  drawing  the  lines 
towards  him.  If  at  the  top  of  a  hill,  begin  by  drawing  the 
lines  from  the  bottom,  and  vice  versa.  To  guide  the  hatch- 
ings, he  should  lightly  sketch  in  the  contour  lines.  Hatch- 
ings must  be  drawn  truly  perpendicular  to  the  contour  lines. 
Where  the  contour  lines  curve  sharply,  it  is  often  well  to 
draw  in  hatchings  at  considerable  intervals  as  a  guide  to  the 
main  body  of  those  drawn  afterwards.  Hatchings  in  adjoin- 
ing rows  should  not  be  contimious,  but  so  drawn  as  to  break 
joints.     They  must  not  overlap,  and  should  be  drawn  in 


MAPPING. 


787 


slightly  ivavy  lines.  In  drawing  a  hill  where  the  slopes  are 
steep  and  irregular,  it  is  often  well  to  draw  auxiliary 
contours. 

An  example  of  this  system  is  given  in  Fig.  3  of  Plate, 
Title:  Contours  and  Slopes,  which  represents  an  abrupt 
promontory.  Its  base  marks  the  channel  of  a  river.  The 
ground  on  the  opposite  side  of  the  river  is  generally  level 
with  occasional  undulations.  The  degree  of  the  slope  is 
indicated  by  the  spacing  of  the  contours  and  the  correspond- 
ing lengths  and  number  of  hatchings.  The  more  abrupt 
the  slope  the  closer  together  the  contours  and   hatchings. 


Fig.  3-13. 
The  preliminary  work  necessary  for  such  a  topographical 
map  is  as  follows:  A  traverse  or  meander  line  is. run,  mark- 
ing the  windings  of  the  stream.  Having  platted  this 
meander  line,  the  topographer  takes  his  book  containing 
the  sketch,  and  from  the  promontory  itself  sketches  in  the 
main  features  of  the  surface.  A  hand  level  is  of  great  ser- 
vice in  determining  relative  elevations.  From  these  notes 
the  final  map  is  made  up,  the  work  being  done  in  the  office. 
Fine  topographical  drafting  should  not  be  attempted  in 
camp.  The  facilities  of  a  well-equipped  office  are  necessary 
to  rapid  and  satisfactory  work.     The  student  is  not  expected 


788  MAPPING. 

to  reproduce  the  exact  outline  of  the  figure^  but  it  is  expected 
that  his  work  will  show  a  proper  understanding  of  the  sub- 
ject. Having  drawn  the  outline  of  the  river,  he  should 
draw  in  the  contours  in  light  pencil  lines,  spacing  them  to 
conform  to  the  different  slopes.  It  will  be  evident  to  the 
student  that  within  the  space  represented  by  Fig.  2  the  sur- 
face of  the  river  at  C  and  D  will  be  practically  the  same. 
Hence,  if  the  distance  from  the  summit  A  to  the  river  at  E 
is  but  half  the  distance  from  A  to  F,  the  slope  A  E  must  be 
twice  as  abrupt  as  the  slope  A  F.  Hence,  the  contours 
which  mark  equal  heights  will  be  twice  as  far  apart  on  the 
slope  A  F  as  on  the  slope  A  E.  He  should  draw  all  the 
contours,  outlining  the  summits  at  A  and  B^  before  com- 
mencing the  hatchings.  The  short  hatchings  on  either  side 
of  the  river  mark  its  banks.  On  the  promontory  side  they 
are  shorter  than  on  the  opposite  side,  as  the  former  has  the 
more  abrupt  banks.  Fig.  3  of  the  same  plate  represents 
an  irregular  and  abrupt  sea  coast.  The  survey  for  such  an 
area  would  embrace  a  traverse  of  the  entire  shore  line — of 
the  island  as  well  as  the  mainland.  This  traverse  line 
should  be  used  as  a  base  line  for  auxiliary  traverse  lines,  by 
means  of  which  the  summits  A,  B,  C\  D,  and  E,  and  any 
other  important  objects  could  be  located.  .  The  heights  of 
these  summits  could  be  determined  either  by  triangulation 
or  by  the  aneroid  barometer.  With  this  information  as  a 
basis,  the  shore  line  is  located,  the  contours  sketched  in,  and 
the  hatchings  drawn.  As  in  the  case  of  Fig.  2,  the  student 
is  not  expected  to  produce  a  literal  copy,  but  to  show  his 
proficiency  by  furnishing  a  clear  and  finished  drawing. 

Hatchings  should  have  their  thickness  and  distance  apart 
proportional  to  the  steepness  of  the  slope.  The  lines  are 
made  heavier  as  the  slope  is  steeper,  being  fine  for  gentle 
slopes,  and  for  very  steep  slopes  the  blank  spaces  are  but 
half  the  breadth  of  the  lines. 

1376.  Third  System— By  Shades  from  Vertical 
I^ight. — The  steeper  the  slope  the  less  light  it  receives. 
In  practice,  the  difference  in  color  is  much  exaggerated. 


MAPPING. 


789 


Various  governments  have  prepared  tables  establishing  the 
ratio  of  color  to  different  slopes.  The  shading  is  applied  in 
various  ways.  A  rapid  method,  and  a  sufficiently  accurate 
one  for  many  kinds  of  work,  is  to  sketch  in  the  contours  and 
then  apply  the  shading  in  the  form  of  India  ink.  Each 
varying  tint  is  applied  with  its  particular  brush,  care  being 
taken  not  to  allow  any  tint  to  dry  before  the  succeeding 
tint  is  applied.  By  this  means  the  tints  are  blended,  giving 
a  smooth  and  finished  effect  to  the  work.  The  tints  are 
made  light  for  gentle  slopes  and  dark  for  steep  slopes,  a 
slope  of  60°  being  black  and  one  of  30°  being  midway 
between  black  and  white,  and  so  on. 

1377.  Shades  by  Contour  Lines. — This  is  accom- 
plished by  interpolating  additional  contour  lines  between 
the  regular  contours.  Confusion  is  likely  to  result  from 
this  method,  especially  where  the  slopes  are  steep,  as  the 
numerous  contours  are  liable  to  run  together  or  be  confused 
with  roads  or  boundaries. 


CONVENTIONAL    SIGNS. 

1378.  Sand,  Rock,  Etc. — Sand  is  represented  by 
fine  dots  made  by  the  point  of  a  pen ;  gravel  by  coarser 
dots.  Rocks  are  represented  by  angular,  irregular  masses, 
as  would  appear  when  seen  from  above  and  drawn  in  their 
proper  places. 

1379.  Signs  for  Vegetation. — Woods  are  repre- 
sented  by    scalloped   circles,    irregularly   placed,    closSr   or 


ttU 

%^^ 

44i^ 

;     i.      /  > 

ill 

11 
ft 

%%.%%% 

^*%  ^^  "^V^^  Ms 

%%<^<^^. 

%<K%%A 

^\^^A. 

Fig.  344. 


Fig.  345. 


Fig.  346. 


farther  apart,  according  as  the  forest  is  dense  or  open. 
Their  shadows  are  drawn  on  their  lower  right-hand  sides,  as 
shown  in  Fig.  :J44.     Sometimes  trees  are  drawn  in  elevation, 


790 


MAPPING. 


as  shown  in  Fig.  345.  This  method  is  not  admissible  ac- 
cording to  the  laws  of  projection,  but  it  is  very  effective, 
and  deciduous  trees  are  more  readily  distinguished  from 
evergreen  by  this  method  than  by  that  shown  in  Fig.  344, 
where  deciduous  trees  are  represented  by  scalloped  circles 
and  evergreens  by  stars. 

Orchards  are  represented  by  trees  in  regular  rows,  as 
shown  in  Fig.  340. 

Bushes  are  drawn  like  trees,  but  in  smaller  figures.  Fig. 
347  represents  bushes  and  trees  intermingled. 


Fig.  347 


FIG.    349. 


Fig.  348. 

Grass  land  is  represented  by  irregular  groups  of  short 
diverging  lines,  as  shown  in  Fig.  348. 

Uncultivated  land  is  shown  by  inter- 
spersing the  signs  of  sand,  grass,  bushes, 
etc. ;  cultivated  land  by  parallel  rows  of 
broken  lines,  as  in  Fig.  349. 

Swamp  land  is    represented   by  grass. 
Fig  350  bushes,  and  water,  as  in  Fig.  350. 

1380.     Shore  Lines.  — The  sea-shore  is  represented  by 
a  line  following  all  its  windings  and  indentations. 


A  short 


FIG.  351. 


MAPPING. 


Idi 


distance  from  the  shore  line,  a  parallel  line  is  drawn,  and  a 
little  further  removed  a  second  parallel,  and  so  on,  as  in 
Fig.  351. 

An  abrupt  and  rocky  shore  is  shown  in  Fig.  352.     The 
irregular  dotted  surfaces  surrounded  by  shore  lines  represent 


•-ri:   -.5^ 


r^-<^.. 


sand  bars.     The  dotted   outlines  beyond    the    shore    lines 
represent  either  shoals  or  sunken  rocks. 


FIG.  353, 


Rivers  have  their  shore  lines  treated  in  the  same  manner 
as  the  sea-shore,  as  shown  in  Fig.  353. 

Large  brooks  are  represented  by  two  parallel  lines;  small 
brooks  by  a  single  line. 


792  MAPPtlSTG. 

1381.  Grounds  and  Gardens.  — Grounds  and  gar- 
dens are  represented  in  plan  as  follows:  The  grounds,  by 
boundaries  of  property  and  street  lines;  the  house  and  other 
buildings,  by  their  ground  plan,  and  drives,  walks,  lawn, 
shrubbery,  and  trees,  by  either  outlines  or  conventional 
signs.  The  gardens  by  rectangular  beds  and  other  forms 
of  arrangement. 

PLATE,     TITLE  :    TOPOGRAPHICAL     MAPS. 

1382.  Fig.  1  of  this  plate  illustrates  the  use  of  conven- 
tional signs  in  practical  landscape  gardening,  affording  the 
student  some  knowledge  of  how  a  given  area  may  be  dis- 
posed so  as  to  combine  artistic  arrangement  with  practical 
utility.  It  contains  a  plat  of  a  house,  grounds,  and  gardens 
drawn  to  a  scale  of  50  feet  to  the  inch.  All  necessary  di- 
mensions are  given  for  an  accurate  reproduction  of  the 
work.  The  student  should  first  carefully  study  the  outlines, 
and  accurately  determine  their  dimensions,  after  which 
the  details  will  be  a  simple  matter. 

In  drawing  Fig.  1,  first  lay  out  the  boundaries  of  the  plat 
of  ground,  375  ft.  front  by  515  ft.  deep. 

The  width  of  the  street  fronting  the  lot  is  60  ft.  From 
the  front  corners  of  the  lot  A  and  A ',  measure  A  B  and  A '  B\ 
each  17^  ft.,  locating  the  center  line  of  the  carriage  drive. 
From  B  and  B'  measure  ]00  ft.,  locating  the  centers  C 
and  C.  From  these  centers  with  equal  radii  C  ^and  C  B' 
describe  equal  arcs  B  D  and  B'  D'  containing  30°.  Pro- 
duce the  radii  C  D  and  C  D'  until  they  intersect  at  E.  If 
the  work  has  been  correctly  done,  E  will  be  equidistant 
from  the  corners  A  and  A' .  Through  E  draw  a  line  E  E' 
at  right  angles  to  the  line  A  A'.  This  line  will  divide  the 
lot  into  two  equal  parts  and  form  the  main  base  line  for  the 
location  of  points  in  the  plat.  With  the  radius  E  D  181  ft. 
in  length  describe  the  arc  D  D\  completing  the  center  line 
of  the  front  carriage  drive.  The  drive  is  15  ft.  in  width. 
The  inner  boundary  is  described  by  simply  reducing  the 
length  of  the  radius  7^  ft.,  and  the  outer  boundary  by  in- 
creasing the  length  an  equal  amount.     We  next  measure 


MAPPING.  793 

from  the  street  corner  A  on  the  left  boundary  the  distance 
A  F=  300  ft.,  and  at  F draw  F  F'  perpendicular  to  A  F. 
At  some  point  G  of  the  main  base  line  E  F',  draw  G  G' 
perpendicular  to  E  E'  and  95  ft.  in  length.  At  G',  the  ex- 
tremity of  this  perpendicular,  draw  a  line  H  H'  perpen- 
dicular to  6^  6"'  intersecting  F  F'  at  /,  which  point  is  the 
center  of  an  elliptical  curve  in  the  carriage  drive.  The 
major  axis  K K'  oi  this  ellipse  is  85  ft.,  and  the  minor  axis 
L  L  is  GG  ft.  in  length.  This  ellipse  the  student  will  draw 
according  to  the  method  described  in  the  section  on  Me- 
chanical Drawing.  Having  drawn  the  ellipse,  the  student 
will  readily  draw  the  border  lines  of  the  drive  by  increas- 
ing or  reducing  the  lengths  of  the  various  radii. 

Draw  both  outer  and  inner  boundaries  of  the  ellipse  in 
pencil  so  as  to  form  closed  figures.  From  some  point  M 
of  the  street  line  draw  MM'  213  ft.  in  length  and  parallel 
to  E  E'.  Through  M'  draw  M'  M\  perpendicular  to  E  E'. 
From  E  E'  and  M'  M"  locate  the  house  from  dimensions 
given.  From  some  point  N  oi  E  E\  draw  A^  A^'  110  ft.  in 
length  "and  perpendicular  to  E  E' .  At  N'  draw  in  both 
directions  an  indefinite  line  perpendicular  to  N N' .  At  some 
point  O  of  the  line  E  E'  erect  a  perpendicular  O  O'  35  ft.  in 
length,  and  through  O'  draw  an  indefinite  line  parallel  to 
E  E'.  From  a  point  O'  of  this  line  with  a  radius  of  100  ft. 
describe  an  indefinite  arc  P  P\  being  careful  that  the 
extremity  ■/*  shall  be  in  a  tangent  to  the  center  line  at  the 
carriage  driveway.  Then,  from  some  point  Q,  found  by 
trial,  with  a  radius  of  50  ft. ,  describe  an  arc  P'  N'  which  shall 
be  tangent  to  the  straight  line  through  A^'  and  the  arc  P  P'. 
In  a  similar  manner  find  centers  at  the  points  7?,  S,  T,  and  U, 
from  which  with  the  given  radii  describe  arcs  forming  the 
center  line  of  the  carriage  driveway.  Having  located  the 
center  line  complete,  the  boundaries  are  put  in  as  previously 
directed,  being  careful  to  unite  the  various  curves  with 
smooth,  even  lines.  The  arc  described  from  the  center  U 
must  be  tangent  to  the  ellipse  and  to  the  center  line  V  V, 
which  is  15^  ft.  distant  from  the  boundary  of  the  lot.  The 
stable  lot  is  75  ft.   square.     The  buildings  may  be  readily 


794  MAPPING. 

located  from  figures  given  in  the  drawing.  The  kitchen 
garden  extends  from  the  rear  boundary  of  the  lot  150  ft. 
towards  the  street,  and  from  the  right-hand  boundary  to  the 
driveway  and  stable  yard.  It  is  divided  into  rectangular 
plots,  the  various  sizes  being  suited  to  the  character  of 
the  vegetables  grown.  All  dimensions  necessary  for  a 
reproduction  of  the  drawing  are  fully  given. 

1383.  Fig.  2  shows  a  portion  of  a  town,  together  with 
its  connections  with  railroad  and  canal.  The  student  will 
make  the  drawing  to  a  scale  of  200  feet  to  the  inch. 

Before  commencing  this  plate  the  student  will  note  that 
the  magnetic  meridian  is  parallel  to  the  rightand  left  borders 
of  the  plate.  At  250  ft.  from  the  S  W  corner  of  the  plat 
we  locate  a  plug,  which  is  the  starting  point  for  the  traverse 
of  the  river.  Call  this  plug  Sta.  1.  Thence,  run  N  22°  30'  E 
734  ft.  to  Sta.  2;  thence,  N  G0°  30'  E  57G  ft.  to  Sta.  3,  the 
center  of  Main  street;  thence,  N  68^  1 5' E  430  ft.  to  Sta.  4. 
At  100  ft.  from  the  starting  point  the  river  is  30  ft.  to 
right ;  at  Sta.  2  it  is  70  ft.  R. ;  at  Sta.  3,  40  ft.  R. ;  at  Sta.  4. 
44  ft.  R.  The  river  has  an  average  width  of  400  ft.  The 
student  will  draw  in  the  shore  line  from  the  offsets  given 
above,  giving  it  the  same  contour  as  shown  in  the  plate. 
The  opposite  shore  the  student  will  locate  by  offsets,  avera- 
ging 400  feet  each.  Again  starting  at  Sta.  3  of  the  river 
traverse,  a  line  is  run  N  16°  W  along  the  center  of  Main 
street,  producing  the  line  backwards  from  Sta.  3  across  the 
river  and  beyond  to  the  boundary  of  the  plat.  The  several 
lines  of  survey  will  be  used  as  base  lines  for  the  location  of 
streets,  railroad  tracks,  canal,  and  all  objects  included  in  the 
map.  The  starting  point  of  each  line  of  survey  is  numbered 
zero,  and  all  lineal  base-line  measurements  are  referred  to 
the  starting  or  zero  points.  Distances  measured  on  the  base 
line  are  expressed  in  stations  of  100  ft.  each,  and  offsets  are 
given  in  full.  Calling  Sta.  3  of  the  river  traverse  0,  we 
measure  northward  to  Sta.  0  +90,  the  north  end  of  the  river 
and  canal  bridge.  The  wing  walls  of  the  abutments  diverge 
at  an  angle  of  30°.   At  Sta.  4  +  93  is  the  center  of  the  track 


MAPPING.  795 

of  the  P.  &  N.  R.  R.,  the  bearing  of  which  is  N  73° 
30'  E. 

At  Sta.  5  +  ^8  is  the  center  of  Putnam  street,  the  bearing 
of  which  is  N  73°  30'  E.  At  Station  11  +  68  is  the  center 
of  Randolph  street,  the  bearing  of  which  is  N  73°  30'  E. 
Produce  the  center  lines  of  both  Putnam  and  Randolph 
streets  until  they  intersect  the  boundaries  of  the  plat.  Main 
street  is  GO  feet  in  width,  and  Putnam  and  Randolph  streets 
are  each  50  feet  in  width.  Draw  parallels  to  the  center  lines 
of  these  streets,  locating  the  proper  boundaries  as  shown  in 
the  plat.  From  the  intersection  of  the  center  line  of  Mam 
with  that  of  Putnam  street,  measure  eastward  on  the  center 
line  of  Putnam  street  450  ft.  to  the  center  of  Tyler  street, 
the  bearing  of  which  is  N  3°  45'  W.  Produce  the  center  line 
of  Tyler  street  northward  until  it  intersects  the  north  bound- 
ary of  the  plat.  On  the  N  E  corner  of  Main  and  Randolph 
streets  is  a  hotel  fronting  110  ft.  on  Main  and  100  feet  on 
Randolph  streets.  The  hotel  has  a  depth  of  60  feet  from 
each  frontage.  On  the  S  W  corner  of  Main  and  Randolph 
streets  is  the  postoffice,  fronting  60  ft.  on  Main  street  and 
40  ft.  on  Randolph  street.  Returning  to  the  starting  point, 
viz.,  Sta.  3  of  the  river  traverse,  and  running  southward  on 
the  center  line  of  Main  street,  at  Sta.  0  +  34  is  the  center 
of  the  shore  pier,  10  ft.  by  40  ft. ;  at  Sta.  2  +  34  is  the  center 
of  the  channel  pier,  12  ft.  by  40  feet,  and  at  Sta.  4  +  34  is 
the  south  end  of  the  bridge.  The  bridge  is  30  feet  wide. 
The  wing  walls  of  the  south  abutment  also  diverge  at  an 
angle  of  30°.  The  south  approach  is  40  ft.  in  width  and  200 
ft.  in  length.  Beyond  the  approach  the  street  has  the  full 
width  of  60  feet. 

At  100  ft.  east  of  the  S  W  corner  of  the  plat  is  the  cen- 
ter line  of  the  S.  &  B.  R.  R.,  which  has  a  double  track,  the 
track  centers  being  spaced  13  ft.  apart.  The  bearing  of  this 
tangent  is  N  15°  15'  E,  and  the  given  point  is  numbered 
Sta.  0.  At  Sta.  5  is  the  center  of  the  towing  path  of  the 
C.  &  O.  canal,  the  bearing  of  which  is  N  54°  30'  E.  At 
Sta.  9  +  44.1  is  the  P.  C.  of  a  6°  curve  L.  for  30°.  The 
student  will  produce  the  center  line  to  Sta.  12,  which  is  the 


796  MAPPING. 

point  of  intersection  for  the  curve,  laying  off  the  tangent 
distance  of  255.9  ft.  Draw  the  center  line  of  each  track, 
spacing  them  6.5  ft.  from  the  main  center  line.  Having 
located  the  center  of  the  6°  curve,  the  parallel  curves  are 
struck  with  a  compass,  increasing  the  radius  6.5  ft.  for  the 
outer  curve  and  diminishing  it  the  same  amount  for  the 
inner  curve.  North  of  Putnam  St.  the  right  of  way  of  the 
S.  &  B.  R.  R.  is  100  ft.,  50  ft.  each  side  of  the  main  center 
line.  Parallel  to  this  center  line  on  each  side  of  the  railroad 
is  a  street  40  ft.  in  width.  Produce  the  center  line  of  the 
ea^  track  of  the  S.  &  B.  R.  R.  until  it  intersects  the  center 
line  at  the  P.  &  N.  R.  R.  The  intersection  angle  is  57°  30'. 
Unite  these  tangents  by  a  10°  curve.  At  Sta.  6  +  63  of  the 
S.  &  B.  R.  R.  west  track,  is  the  P.  C.  of  a  16°  curve  L.  for 
27°,  which  we  call  track  A. 

At  40  ft.  from  the  P.  T.  of  this  curve  is  the  center  of  a 
turntable,  the  diameter  of  which  is  60  ft.  From  the  cir- 
cumference of  the  turntable  to  the  inner  wall  of  the  round- 
house is  60  ft.  The  right-hand  end  wall  of  the  roundhouse 
faces  on  a  radial  line  from  the  center  of  the  turntable,  which 
line  makes  an  angle  of  30°  30'  with  the  tangent  of  the  turn- 
out curve.  The  left-hand  end  wall  is  similarly  situated, 
making  an  angle  of  91°  30'  with  the  tangent  of  the  turnout 
curve.  The  depth  of  the  stalls  is  70  ft.  The  tracks  at  the 
inside  wall  line  are  spaced  15-ft.  centers.*  From  the  center 
of  the  outside  track  to  outside  of  end  walls  is  10  ft.  At 
Sta.  8  +  92  of  the  west  track  is  the  P.  C.  of  a  16°  turnout 
curve,  to  left,  for  30°  10'.  This  we  call  track  B.  The  P.  T. 
is  on  the  line  of  the  south  end  wall  of  a  car  shop.  The  side 
walls  of  the  car  shop  are  parallel  to  the  tangent  of  the  curve. 
The  east  wall  is  15  ft.  from  the  center  line  of  the  tangent 
and  the  west  wall  50  ft.,  giving  a  total  width  of  65  ft.  The 
length  of  the  car  shop  is  200  ft.  At  the  northwest  corner  of 
the  car  shop  is  an  engine  and  boiler  house  40  ft.  square. 

On  the  north  side  of  Putnam  street  is  a  foundry,  fronting 
120  ft.  on  Putnam  street  and  175  ft.  on  Foundry  street,  the 
building  having  a  depth  of  50  ft.  from  both  frontages.  The 
east  side  of  the  building  is  parallel  to  the  tangent  of  the 


MAPPING.  797 

turnout  curve  leading  to  the  car  shop,  and  10  ft.  from  it. 
At  Sta.  11-]- 55,  as  measured  on  the  produced  tangent  of 
the  S.  &  B.  R.  R.  is  the  south  end  of  the  platform  of  the 
R.  R.  station.  At  Sta.  12  is  the  south  end  of  the  station 
proper.  The  station  is  G7  ft.  long,  as  measured  on  this  tan- 
gent. The  outer  edge  of  the  platform  is  8  ft.  from  the  cen- 
ter line  of  the  adjacent  tracks.  The  platform  is  10  ft.  wide 
and  extends  on  all  sides  of  the  station,  the  curved  walls  of 
which  are  parallel  to  the  railroad  tracks. 

At  Sta.  8  of  the  S.  &  B.  R.  R.  is  the  P.  C.  of  a  1G°  turn- 
out curve  R.,  which  leads  from  the  east  track,  containing 
39°  50',  and  called  track  C.  A  tannery,  300  ft.  in  length  by 
90  ft.  in  width,  extends  from  the  P.  T.  of  this  curve,  parallel 
to  and  20  ft.  to  the  right  of  the  center  line  of  the  tangent. 
A  bark  shed  of  the  full  width  of  the  tannery  forms  a  con- 
tinuation of  the  tannery  and  extends  to  Main  street.  A 
platform  10  ft.  in  width  extends  the  entire  length  of  the 
tannery,  between  it  and  the  tracks.  At  the  southwest  cor- 
ner of  the  tannery  is  an  engine  and  boiler  house  50  by  80  ft. 
At  GO  ft.  from  the  P.  C.  of  track  C  and  tangent  to  that 
curve,  track  D  commences. 

At  54  ft.  from  the  commencement  of  track  D  is  the  P.  C. 
of  a  23°  curve  R.  for  28°  38',  and  called  track  E,  which  ter- 
minates in  a  tangent  parallel  to  the  tangent  of  track  C,  and 
spaced  12  ft.  from  it.  At  364  ft.  from  the  P.  T.  of  track 
£  is  the  west  end  of  a  coal  chute.  The  south  side  of  the 
chute  is  8  ft.  from  the  center  of  the  track;  the  north  side 
is  22  ft.  from  the  center  of  the  track,  which  gives  the  build- 
ing a  total  width  of  30  ft.  It  extends  in  length  to  Main 
street.  At  257  ft.  from  the  commencement  of  track  D  is 
the  P.  C.  of  a  1G°  curve  R.  for  31°,  and  called  track  F.  At 
8  ft.  to  the  right  and  parallel  to  the  tangent  of  this  curve 
is  a  freight  depot,  extending  from  the  P.  T.  of  the  curve  and 
200  ft.  long  by  35  ft.  wide.  On  the  south  side  the  freight 
station  is  a  platform  10  ft.  wide,  extending  its  entire  length. 
At  312  ft.  from  the  commencement  of  track  D  is  the  P.  C.  of 
a  23°  curve  R.  for  31°,  the  tangent  of  which  is  parallel  to 
track  F,  their  center  lines  being  spaced  12  ft. 


798  MAPPING. 

Between  Sta.  5  +  78  of  the  S.  &  B.  R.  R.  west  track,  and 
Sta.  7  +  51,  east  track,  is  a  cross-over  track,  which  we  call 
track  G.  Thi»  consists  of  two  turnout  curves,  one  com- 
mencing at  each  of  the  given  stations  and  intersecting  on 
the  main  center  line.  The  curve  commencing  at  Sta.  5  +  78 
is  a  9°  30' curve  R.  ;  the  curve  commencing  at  Sta.  7  +  51  is 
also  a  9°  30'  curve  R.,  but  described  in  the  opposite  direc- 
tion. If  carefully  drawn,  these  curves  will  intersect  on  the 
main  center  line.  Between  Sta.  14  +  44.1,  east  track,  and 
Sta.  16  +  17.1,  west  track,  is  another  cross-over,  which  we 
call  track  H.  The  curves  are  both  9°  30',  described  in 
opposite  directions,  as  in  the  preceding  case. 

Starting  at  Sta.  5  of  the  S.  &  B.  R.  R.,  which  is  directly 
over  the  center  line  of  the  towpath  of  the  C.  &  O.  canal, 
the  bearing  of  which  is  N  54°  30'  E,  we  measure  north- 
eastward along  the  center  line  of  the  towpath  706  ft.  to  the 
P.  C.  of  a  12°  R.  for  12°.  Produce  the  back  and  forward 
tangents  of  this  curve  until  they  intersect  the  borders  of 
the  plat.  The  towpath  is  12  ft.  wide  and  the  canal  40  ft. 
wide.  The  canal  makes  the  same  curve  as  the  towpath,  the 
arcs  being  struck  from  the  common  center.  The  student 
will  draw  the  boundaries  of  the  canal  and  towpath  in  ink, 
but  need  not  ink  in  the  center  line  of  the  towpath.  The 
north  abutment  of  the  Main  St.  canal  and  river  bridge  is 
4  ft.  from  the  boundary  of  the  canal.  At  443  ft.  from  our 
starting  point  on  the  towpath  is  the  west  end  of  a  canal 
dock,  which  consists  of  a  widening  of  the  canal  in  which 
boats  are  moored  while  their  cargoes  are  being  dis- 
charged. This  dock  is  240  ft.  long  and  20  ft.  wide,  provi- 
ding berths  for  four  boats.  At  120  feet  from  the  west  end  of 
the  dock  is  the  west  end  of  a  coal  chute,  the  south  side  of 
which  is  parallel  to  and  20  ft.  from  the  dock.  The  coal 
chute  is  40  by  200  ft.  The  railroad  bridge  over  the  canal  is 
30  ft.  wide.  The  south  abutment  is  placed  12  ft.  and  the 
north  abutment  6  ft.  from  the  canal,  both  abutments  being 
parallel  to  the  canal.  The  outer  faces  of  the  wing  walls  of 
these  abutments  are  parallel  to  and  10  ft.  from  the  center 
line  of  the  nearest  track. 


MAPPING.  799 

PLATE,  TITLE:    MAP    OF    A    VILLAGE. 

1384.  This  plate  represents  a  topographical  map  of  a 
village.  In  making  a  survey  of  this  description  the  engineer 
will  select  for  a  starting  point  some  well-defined  landmark ; 
but  as  there  are  a  score  of  points  to  choose  from,  the  choice 
will  depend  upon  the  judgment  of  the  engineer.  The  in- 
tersection of  the  center  lines  of  two  highways  or  the  head 
block  of  a  railroad  switch  are  excellent  points  from  which  to 
commence  a  survey.  The  center  lines  of  highways  and 
railroads  are  the  base  lines  from  which  the  minor  details, 
such  as  houses  and  other  buildings  are  located.  The  quickest 
and  best  method  of  locating  a  building  is  to  set  a  temporary 
plug  on  the  base  line  near  the  building.  Set  up  the  transit 
at  this  point  and  measure  the  angles  between  the  base  line 
and  two  consecutive  angles  of  the  building,  measuring  the 
distances  from  the  plug  to  the  angles  of  the  building.  These 
angles  and  distances  will  locate  one  side  of  the  building.  A 
small  free-hand  sketch  is  then  made,  giving  the  base  line, 
the  station  of  the  plug,  or  its  distance  from  some  known 
point,  and  the  angles  and  distances  to  the  side  of  the  build- 
ing. The  remaining  sides  of  the  building  are  added  to  the 
sketch  and  their  several  lengths  measured  in  consecutive 
order  and  marked  on  the  sketch.  These  notes  are  quickly 
made  and  as  quickly  platted. 

Sketches  are  of  the  greatest  value  in  taking  topographical 
notes.  They  can  be  made  in  less  than  half  the  time  re- 
quired for  a  full  description,  and  are  always  more  intelligi- 
ble to  the  draftsman.  Each  surveyor  has  his  individual 
methods,  both  in  order  of  work  and  form  of  notes,  and 
often  one  will  consume  twice  as  much  time  as  another  in 
performing  the  same  work ;  but  expedition  is  of  no  value  if 
had  at  the  cost  of  accuracy. 

In  this  map  all  the  conventional  signs  suited  to  an  area  of 
such  magnitude  are  employed.  The  student  will  draw  the 
map  to  a  scale  of  200  feet  to  the  inch.  The  magnetic  merid- 
ian is  parallel  to  the  right  and  left  borders  of  the  plate, 
the  north  point  being  at  the  top  of  the  map.  The  center 
lines  of  the  highways  are  given,  together  with  their  mag- 


800  MAPPING. 

netic  bearings,  widths,  and  distances  between  the  angles 
made  by  the  center  line.  The  center  line  of  the  railroad  is 
represented  by  a  heavy,  full  line,  and  the  boundaries  of  the 
right  of  way,  which  is  100  feet  in  width,  are  represented  by 
light  full  lines.  The  magnetic  bearings  of  the  tangents  are 
given  and  the  stations  of  the  points  of  curve  and  tangent 
from  which  the  lengths  of  the  tangents  are  found  by  sub- 
tracting the  station  of  the  P.  T.  of  one  curve  from  the 
P.  C.  of  the  succeeding  curve.  The  curves,  instead  of 
being  run  in  from  intersections  of  tangents,  are  platted  as 
follows: 

The  location  of  the  first  tangent  in  the  map  being  given 
by  references  to  the  boundary  lines  of  the  map,  and  the 
P.  C.  of  the  first  curve  denoted  by  its  station,  a  perpendicu- 
lar is  erected  to  the  given  tangent,  and  upon  it  the  length 
of  the  radius  of  the  required  curve  is  laid  off  to  the  given 
scale.  Then,  from  the  given  center  the  curve  is  struck  with 
a  compass,  being  careful  that  the  arc  so  struck  shall  contain 
as  many  degrees  as  the  central  angle  of  the  curve,  the 
central  angle  of  the  curve  being  laid  off  with  a  protractor. 
The  intersection  of  the  second  radius  with  the  arc  will  be 
the  P.  T.  of  the  following  tangent.  A  perpendicular  is  then 
erected  to  the  second  radius  and  tangent  to  the  arc  at  the 
given  intersection.  The  P.  C.  of  the  next  curve  being  given, 
its  length  is  readily  found  by  subtraction.  The  borders  of 
the  lake  are  located  by  offsets. 

The  student  is  not  expected  to  exactly  duplicate  the 
topography,  but  give  the  same  general  effect.  All  bound- 
aries whose  magnetic  bearings  are  given  and  the  location  of 
all  buildings  he  must  faithfully  repeat  in  his  drawing. 

1385.  Starting  at  the  northwest  corner  K  of  the  map 
we  measure  eastward  along  the  north  boundary  TOO  ft.  to 
Z,  the  center  of  the  S.  &  L.  R.  R.,  the  bearing  of  which  at 
that  point  is  S  7°  45'  E.  At  310  feet  from  this  point  is  the 
P.  C.  of  an  8°  curve  R.,  which  we  call  Sta.  40  +  60.  The 
central  angle  of  this  curve  is  25°,  and  its  length  312.5  ft 
The  station  of  the  P.  T.  we  find  by  adding  the  length  of  the 


MAPPING.  801 

curve  to  the  station  of  the  P.  C,  giving  43  +  72.5  for  the 
P,  T.  of  the  curve.  The  bearing  of  the  forward  tangent  is 
S  17°  15'  W  and  its  length  400  ft.,  making  the  station  of 
the  next  P.  C.  47  +  72.5.  This  curve  is  9°  R.  and  its  central 
angle  is  15".  Its  length  is,  therefore,  1G6.7  ft.,  and  the  sta- 
tion of  the  P.  T.  49+39.2.  The  bearing  of  the  forward 
tangent  is  S  32°  15'  W,  found  by  adding  the  central  angle 
of  15°  to  the  bearing  of  the  preceding  tangent.  The  length 
of  the  forward  tangent  is  GIO  ft.  to  Sta.  55  +  49.2,  which  is 
the  P.  C.  of  a  6°  curve  L.  The  curve  is  continued  to  the 
south  boundary  of  the  map. 

The  switch  extending  to  the  ice  houses  along  the  shore  of 
the  lake  is  located  as  follows : 

Scale  off  from  the  northwest  corner  K  of  the  map,  along 
the  north  boundary  790  ft.,  eastward  to  the  point  M.  From 
this  point  as  a  center,  lay  off  with  a  protractor  to  the  right 
of  the  north  boundary  an  angle  of  32°  30'.  The  bearing  of 
this  line  is  S  57°  30'  E.  Scale  47  ft.  on  this  line  from  the 
point  in  the  boundary  where  the  angle  is  turned.  This  will 
locate  the  P.  C.  of  a  16°  curve  R.,  the  station  of  which  is 
3  +  04.7.  The  central  angle  of  this  curve  is  62°  05',  and  the 
station  at  the  P.  T.  6  +  92.7.  The  bearing  of  the  forward 
tangent  is  S  4°  35'  W.  The  next  curve  is  10°  R.  Its  P.  C. 
is  at  Sta.  10+93.7,  and  its  central  angle  is  9"  40',  which 
brings  the  P.  T.  at  Sta.  11  +  89.4.  The  bearing  of  the  for- 
ward tangent  is  S  14°  15'  W.  The  next  curve  is  also  10°  R. 
Its  P.  C.  is  at  Sta.  15  +  49.4,  and  its  central  angle  27°  30', 
which  brings  the  P.  T.  at  Sta.  18  +  24.4.  The  bearing  of 
the  forward  tangent  is  S  41°  45'  W.  The  last  curve  is  10° 
L.  Its  P.  C.  is  at  Sta.  24  +  24.4,  and  its  central  angle  is 
27°  10',  which  brings  the  end  of  the  line  at  Sta.  26  +  96.1. 

With  a  protractor  lay  off  from  the  P.  C.  of  the  16°  curve 
of  the  ice  switch,  a  central  angle  of  18°.  Draw  a  radius  in- 
cluding this  angle  and  at  its  extremity  draw  a  tangent  to 
the  curve,  with  bearing  of  S  39°  30'  E.  This  point  of  tan- 
gent is  the  starting  point  of  a  switch  leading  to  a  coal  chute. 
This  point  we  call  Sta.  0.  At  Sta.  0  +  65  of  this  track  is  the 
P.  C.  of  an  18°  curve  R.  for  36°,  bringing  the  P.  T.  at  Sta. 


802  MAPPING.    ' 

2  +  65.  At  this  point  the  track  enters  a  coal  chute  50  ft.  long 
by  30  ft.  wide.  The  center  line  of  the  track  is  parallel  to 
the  sides  of  the  chute  and  spaced  7  ft.  from  the  west  side. 
At  120  ft.  from  the  starting  point  of  the  S.  &  L.  R.  R.  is  the 
north  end  of  platform  of  a  railroad  station,  and  at  210  ft.  from 
that  point  is  the  south  end  of  the  platform.  The  edge  of  this 
platform  is  spaced  G  ft.  from  the  center  line  of  the  railroad 
track.  The  platform  is  46  ft.  in  width  at  the  north  end  and 
50  ft.  in  width  at  the  south  end.  The  center  line  of  a  road 
40  ft.  wide  commences  at  the  middle  point  of  the  south  end 
of  the  railroad  station  platform,  and  extends  in  the  direc- 
tion S  48°  30'  E  500  ft.,  where  it  intersects  with  the  center 
line  of  the  Scranton  turnpike,  the  bearing  of  which  is  S  21° 
30'  W.     Call  this  point  of  intersection  A. 

Starting  from  intersection  A,  the  traverse  of  the  center 
line  of  the  turnpike  is  as  follows:  S  21°  30'  W  310  ft.; 
thence,  S  58°  30'  E  80  ft.  to  the  west  end  of  a  bridge  20  ft. 
wide;  thence,  by  same  course  40  ft.  to  east  end  of  bridge; 
thence,  by  same  course  80  ft.  to  an  intersection  with  center 
line  of  Andrews  lane.  Call  this  point  of  intersection  B. 
Thence,  S  11°  30'  W  300  ft.  to  intersection  with  center  line 
of  Waverly  road.  Call  this  point  of  intersection  C.  Thence, 
by  same  course  300  ft. ;  thence,  S  8°  30'  E  250  ft. ;  thence, 
S  27°  E  345  ft.  to  north  end  of  a  stone  bridge  20  ft.  wide; 
thence,  by  same  course  30  ft.  to  south  end  of  stone  bridge ; 
thence,  by  same  course  125  ft.  to  an  intersection  with  the 
center  line  of  Newton  road,  the  direction  of  which  is  N  63° 
E  and  width  40  ft.  Call  this  intersection  point  D.  From 
intersection  D  the  turnpike  extends  in  the  direction  N  83°  E 
400  ft.,  thence,  S  76°  E  325  ft.;  thence,  S  46°  E  to  the 
south  boundary  of  the  map.  The  width  of  this  turnpike  is 
50  ft. 

Next  we  measure  from  the  northwest  corner  K  of  the 
map,  southward  along  the  west  boundary  344  ft.  to  the  cen- 
ter A^  of  the  Benton  road.  From  thence  we  measure  along 
the  center  line  of  the  road,  N  80°  15'  E  356  ft. :  thence, 
S  69°  45'  E  350  ft. ;  thence,  S  89°  45'  E  45  ft.  to  west  end  of 
a  culvert  2^  ft.  in  width;  thence,  by  same  course,  50  ft.  tq 


MAPPING.  803 

east  end  of  culvert;  thence,  by  same  course,  crossing  the  ice 
switch  and  road  leading  to  the  railroad  station  and  continu- 
ing to  an  intersection  with  the  Scranton  turnpike,  which  is 
the  terminus  of  the  Benton  road.  Call  this  point  of  inter- 
section E. 

Starting  at  intersection  C,  we  follow  the  center  line  of  the 
Waverly  road  as  follows:  S  55°  15'  E  197  ft.  to  its  intersec- 
tion with  the  center  line  of  Lenox  lane.  This  point  of  in- 
tersection we  call  F.  Thence,  N  74°  45'  E  500  ft. ;  thence, 
S  85°  15'  E,  intersecting  the  old  Scranton  and  Montrose 
turnpike  and  extending  by  the  same  course  to  the  east 
boundary  of  the  map. 

Returning  to  the  point  F^  the  intersection  of  the  center 
line  of  the  Waverly  road  with  Lenox  lane,  we  prolong 
the  line  C  F  from  F,  a  distance  of  290  ft»  This  forms  the 
center  line  of  Lenox  lane,  and  intersects  with  the  center  line 
of  Henderson  lane.  These  intersecting  center  lines  form 
an  angle  of  90°  with  each  other,  making  the  course  of 
Henderson  lane  N  34°  45'  E.  Produce  the  center  line  of 
this  lane  in  both  directions,  intersecting  on  the  south  with 
the  Scranton  turnpike,  and  on  the  north  with  the  Waverly 
road.  The  widths  of  the  Waverly  road  and  Lenox  and 
Henderson  lanes  are  each  40  ft.  Commencing  at  the  point 
B,  where  the  Scranton  turnpike  intersects  the  center  line  of 
Andrews  lane,  we  follow  the  center  line  of  that  lane  in  the 
direction  N  31°  30'  E  300  ft.  to  an  intersection  with  the  cen- 
ter line  of  a  private  lane  leading  in  the  direction  S  85°  30'  E 
200  ft.,  where  it  turns  at  right  angles,  40  ft.  to  the  right 
and  75  ft.  to  the  left.  Continuing  along  the  center  line  of 
Andrews  lane  by  the  same  course  100  ft.,  we  change  the 
direction,  running  N  11°  30'  E,  intersecting  with  Hall  road. 
The  width  of  Andrews  lane  is  30  ft. 

Starting  from  the  southeast  corner  O  of  the  map,  we 
measure  westward  along  the  south  boundary  320  ft.  to  the 
center  /'of  the  old  Scranton  and  Montrose  turnpike.  From 
this  point  we  follow  the  center  line  of  the  turnpike  as  fol- 
lows: N  27°  45'  W  440  ft.;  thence,  N  7°  45'  W  330  ft.; 
thence, N  2°  15'  E  1,280  ft.,  intersecting  the  Waverly  and  Hall 


804  MAPPING. 

roads.  The  latter  intersection  makes  the  eastern  limit  of 
Hall  road.  Thence,  N  5°  45'  W  to  the  north  boundary  of 
the  map.  The  width  of  this  turnpike  is  50  ft.  Returning 
to  point  E^  the  terminus  of  the  Benton  and  Hall  roads,  we 
follow  the  center  line  of  Hall  road  S  89°  45'  E  1G5  ft.  to  the 
west  end  of  a  bridge  20  ft.  wide ;  thence,  by  same  course, 
30  ft.  to  east  end  of  bridge;  thence,  by  same  course,  400 
ft.  to  an  intersection  with  the  center  line  of  Prospect  road, 
which  extends  in  the  direction  N  40°  15'  E  to  the  north 
boundary  of  the  map.  Call  this  point  of  intersection  G. 
From  the  point  G  the  center  line  of  Hall  road  extends  in 
the  same  direction,  viz.,  S  89°  45'  E  to  its  intersection  with 
the  center  line  of  the  old  Scranton  and  Montrose  turnpike. 
Call  this  intersection  point  H.  The  widths  of  the  Hall  and 
Prospect  roads  are  40  feet. 

The  right  of  way  of  the  S.  &  L.  R.  R.  is  100  ft.  in  width, 
50  ft.  each  side  of  the  center  line,  excepting  at  the  station, 
where  the  railroad  company's  property  extends  in  width  100 
ft.  on  the  east  side  from  the  center  line  of  the  track,  and  in 
length  from  the  north  boundary  of  the  map  to  the  highway. 
On  the  west  it  extends  in  width  200  ft.  from  the  center  line 
of  the  track  and  in  length  from  the  north  boundary  of  the 
map  to  the  Benton  road.  At  a  point  390  feet  from  Sta. 
43  +  72.5  of  the  main  track,  as  measured  on  the  west  right 
of  way  boundary,  is  the  end  of  the  boundary  line  between 
lands  of  James  Henderson  and  John  Andrews,  the  bearing 
of  which  is  S  57°  45'  E.  This  boundary  extends  to  the  west 
boundary  of  the  map.  At  a  point  in  the  center  of  Hall 
road,  10  feet  west  of  intersection  G,  is  a  corner  at  the 
schoolhouse  lot  which  fronts  100  feet  on  Hall  road,  and  220 
feet  in  depth,  as  measured  from  the  center  line  of  the  road, 
the  sides  being  at  right  angles  to  the  center  line  of  the  road. 
All  property  lines  bounding  on  or  intersecting  higlnvays  follow 
or  extend  to  the  center  line  of  the  highway.  Immediately 
adjoining  the  schoolhouse  lot  on  the  west  is  the  lot  of  John 
Stark,  with  front  of  200  ft.  and  depth  of  220  ft.  A  point 
300  ft.  east  of  intersection  6",  as  measured  on  the  center 
line  of  Hall  road,  is  a  corner  of  lot  of  F.  Swartz.     This 


MAPPING.  805 

boundary  is  at  right  angles  to  the  center  line  of  Hall  road 
and  extends  to  the  center  of  Prospect  road.  The  other 
boundaries  of  the  lot  are  marked  by  the  center  lines  of  the 
roads  upon  which  the  lot  fronts.  At  a  point  300  ft.  south 
of  intersection  //,  as  measured  on  the  center  line  of  the  old 
turnpike,  is  a  corner  of  lot  belonging  to  John  Edwards. 
The  sides  of  the  lot  are  at  right  angles  to  the  center  line  of 
the  turnpike  and  the  ends  parallel.  The  lot  fronts  300  ft. 
on  the  turnpike  and  has  a  depth  of  425  ft.  The  south 
boundary  of  this  lot  forms  a  part  of  the  north  boundary  of  a 
lot  belonging  to  Jane  Gregory.  A  line  joining  the  south- 
west corner  of  John  Edwards's  lot  with  the  northeast  corner 
of  Henry  Watson's  lot  completes  the  north  boundary  of  the 
Gregory  lot.  The  bearing  of  this  line  is  N  87°  10'  E.  The 
west  boundary  has  a  bearing  of  N  4°  45'  E,  and  extends  to 
the  center  line  of  Waverly  road,  with  which  it  forms  an 
angle  of  90°.  The  south  and  east  boundaries  of  the  lot  are 
formed  by  the  center  line  of  the  Waverly  road  and  the  old 
turnpike,  the  courses  of  which  are  already  given.  The 
point  of  intersection  of  the  center  line  of  the  Waverly  road 
with  the  old  turnpike  is  a  corner  of  lot  belonging  to  A. 
Atherton.  The  north  boundary  extends  along  the  center 
line  of  Waverly  road  425  feet;  thence,  at  right  angles  to 
that  road,  S  4°  45'  W  420  ft.  ;  thence,  on  a  line  parallel  to 
the  Waverly  road,  to  the  center  of  the  old  turnpike.  The 
west  boundary  is  formed  by  the  center  line  of  the  turnpike. 
The  west  boundary  of  lot  belonging  to  Jane  Gregory 
forms  the  east  boundary  of  lot  belonging  to  Henry  Watson, 
which  has  a  frontage  of  150  feet  and  a  depth  of  220  feet. 
The  west  boundary  of  Henry  Watson's  lot  forms  the  east 
boundary  of  lot  belonging  to  James  Lenox,  and  extends 
N  4°  45'  E  220  from  the  center  of  the  Waverly  road. 
Thence,  N  85°  15'  W  to  the  center  of  the  Scranton  turn- 
pike. The  remaining  boundaries  of  the  Lenox  lot  are 
formed  by  the  center  lines  of  the  adjoining  highways.  By 
prolonging  the  boundary  between  Henry  Watson  and  James 
Lenox  northward  275  feet,  we  form  the  east  boundary  of 
John  Andrews's  lot.     The  same  line  prolonged  to  the  center 


806  MAPPING. 

of  Hall  road  forms  the  east  boundary  of  Clayton  Andrews's 
lot.  The  boundary  between  lots  of  John  and  Clayton 
Andrews  is  formed  by  the  center  line  of  the  lane,  and  that 
center  line  produced  to  the  east  boundary  of  the  lots.  The 
remaining  boundaries  of  these  lots  are  formed  by  the  center 
lines  of  the  adjacent  highways.  At  210  feet  from  inter- 
section Cy  as  measured  on  the  center  line  of  the  Waverly 
road  and  Lenox  lane,  is  the  northwest  corner  of  a  lot  belong- 
ing to  the  Lenox  estate.  This  lot  has  a  front  of  GO  feet  and 
a  depth  of  180  feet,  the  sides  being  at  right  angles  to  the 
center  line  of  Lenox  lane. 

All  buildings  the  student  will  locate  by  eye,  giving  to 
them  the  same  shape  and  proportions  as  shown  in  the  plate. 
Shade  trees  are  spaced  50  feet,  their  rows  being  placed 
10  feet  inside  the  road  boundaries.  Fruit  trees  are  spaced 
40  and  30  feet.  The  usual  conventional  signs  are  employed 
to  represent  the  topography.  As  grass  and  cereals  are  much 
alike  in  appearance,  the  conventional  sign  for  grass  may  be 
varied  so  as  to  represent  them  all  and  so  give  variety  to  the 
drawing.  A  part  of  the  lot  belonging  to  James  Henderson 
is  occupied  by  a  vineyard,  which  is  represented  by  rect- 
angles enclosed  in  wavy  outlines.  These  signs  might  also 
be  used  to  represent  small  fruits  growing  on  trellises.  All 
other  conventional  signs  employed  have  been  previously 
described,  with  appropriate  illustrations. 

1 386.  Colored  Topography. — All  conventional  signs 
so  far  described  are  made  with  a  pen.  Often,  where  sur- 
veys cover  extensive  areas,  the  labor  and  time  for  pen  work 
can  not  be  spared,  and  colors  applied  with  a  brush  are  used 
instead.  With  a  skilful  hand,  work  of  this  character  may 
be  rapid  and  very  effective.  But  three  colors  besides  India 
ink  are  required;  gamboge  (yellow),  indigo  (blue),  and  lake 
(scarlet).  The  colors  used  in  the  drafting  room  are  of 
two  kinds,  viz.,  dry  and  moist.  Dry  colors  are  sold  in  the 
form  of  rectangular  cakes,  wrapped  in  tin  foil.  Moist  colors 
are  packed  in  small  dishes  of  porcelain.  These  dishes  are 
rectangular  in  form,  open  at  top.     The  surface  of  the  paint 


MAPPING.  807 

is  covered  with  wax  and  the  entire  dish  wrapped  in  tinfoil. 
In  using,  rub  the  cake  of  color  with  a  moistened  brush 
which  will  take  up  sufficient  color.  Dilute  the  color  in 
water  to  the  proper  tint,  which  should  always  be  light  and 
delicate.  To  cover  a  surface  with  a  uniform  tint,  use  a 
camel's  hair  or  sable  brush.  Use  a  separate  brush  for  each 
tint  and  provide  plenty  of  dishes  for  the  various  colors. 
Confusion  in  the  use  of  brushes  is  sure  to  spoil  a  tint.  For 
large  masses  of  the  same  tint,  a  large  brush  should  be  used, 
but  for  vegetation  or  small  details,  small  brushes  are  indis- 
pensable. Avoid  heavy  strokes.  Light  and  rapid  strokes 
produce  smooth  and  pleasing  effects.  The  map  should  be 
pinned  to  a  light  drawing  board,  so  that  it  may  readily  be 
inclined  at  an  angle.  Keep  the  brush  well  filled  with  color 
and  begin  at  the  top  of  the  surface,  inclining  the  board 
towards  you.  If  the  outline  is  very  irregular,  moisten 
the  edge  with  water.  Apply  the  tint  the  full  length 
of  the  surface  and  continue  it  down  the  surface,  7iever 
allowing  the  edge  to  dry,  which  is  the  secret  of  a  smooth 
tint. 

Woods  are  commonly  colored  yellow;  grass  land,  green, 
made  of  gamboge  and  indigo;  cultivated  land,  brown,  made 
of  lake,  gamboge,  and  India  ink;  brushwood,  marbled  green 
and  yellow;  vineyards,  purple,  made  of  lake  and  indigo; 
lakes  and  rivers,  of  light  blue,  with  a  darker  tint  at  the 
shore  line;  seas,  dark  blue,  with  a  little  yellow  added; 
marshes,  the  water  blue,  with  patches  of  green  applied  hori- 
zontally, and  roads,  dark  brown.  Woods  may  be  made  very 
effective  by  drawing  the  trees,  coloring  the  angle  towards 
the  light  (the  upper  left  hand)  with  a  touch  of  yellow,  and 
indigo  on  the  opposite,  or  lower,  right-hand  side. 

Skill  and  judgment  in  mixing  and  applying  colors  can  be 
acquired  only  by  practice.  When  a  combination  tint,  such 
as  brown,  is  required,  the  draftsman  must  estimate  how 
much  coloring  is  required  and  provide  accordingly.  He  is 
liable  to  use  too  much  color  producing  a  heavy  tint,  which 
is  almost  certain  to  become  streaked  when  applied.  A 
separate  brush  should  be  used  to  take  up  each  color,  the 


808  MAPPING. 

brush  being  moistened  and  rubbed  on  the  cake.  A  tinting 
dish  of  either  glass  or  porcelain  contains  the  water.  The 
brushes  carrying  the  colors  are  dipped  into  the  water,  each 
giving  off  its  proportion  of  color.  The  water  is  then  stirred 
until  every  particle  of  color  is  dissolved.  If  the  tint  is  too 
light,  add  more  color;  if  too  heavy — a  common  fault — add 
more  water  until  the  proper  shade  is  obtained.  Any  tint  is 
deepened  by  repeating  the  application  of  it.  When  a  tint  is 
to  be  shaded  from  light  to  dark,  give  the  entire  surface  one 
coat,  which  will  give  the  lightest  shade.  Decide  how  many 
coats  are  to  be  applied  to  produce  the  deepest  tint  and 
divide  the  length  of  the  surface  into  the  same  number  of 
equal  spaces.  Beginning  at  the  top  of  the  surface  to  be 
shaded,  apply  a  second  coat,  stopping  one  space  from  the 
bottom.  Then  take  a  clean  brush  and  dip  it  into  clear 
water  and  wash  the  edge  of  the  second  coat  at  its  finishing 
line,  brushing  downwards,  taking  up  in  the  brush  all  excess 
of  coloring  matter.  Another  coat  is  then  applied,  com- 
mencing again  at  the  top  and  stopping  two  spaces  from  the 
bottom,  washing  down  the  edge  with  clear  water.  The 
paper  must  not  be  allowed  to  dry  between  the  successive 
applications  of  the  tint.  If  from  any  cause  it  should  be- 
come dry,  the  entire  surface  must  be  moistened  with  clear 
water  before  another  application  of  the  tint.  Careful  prac- 
tice will  enable  the  student  to  produce  a  smooth  tint. 
When  a  marbled  effect  is  desired,  first  cover  the  entire  sur- 
face with  one  tint  and  then  apply  the  other  in  shorter  or 
longer  strokes  of  the  brush,  according  to  the  effect  which  it 
is  desired  to  produce. 

In  tinting  shore  lines,  first  trace  the  outline  of  the  shore 
with  a  brush  moistened  with  clear  water,  extending  the  wash 
as  far  as  the  tint  is  to  be  used.  Prepare  a  color  dark  blue  in 
shade.  Next  dip  a  fine  brush  in  the  color  and  trace  the  out- 
line of  the  shore.  The  adjoining  paper  being  moist  will  cause 
the  color  to  run.  Then  moisten  a  brush  in  clear  water  and 
wash  the  shore  line,  the  strokes  of  the  brush  being  drawn 
from  the  shore.  The  effect  will  be  a  dark  blue  shore  line 
shaded  to  light  blue.     The  dark  brown  color  for  roads  is 


MAPPING.  809 

produced  by  adding  India  ink  to  the  brown  representing 
grass  land, 

1387.  Scales. —  The  scale  of  a  topographical  map 
should  depend  upon  the  character  of  the  work  involved,  but 
should  always  be  large  enough  to  clearly  admit  all  necessary 
details  without  making  the  map  unwieldy.  The  work  should 
be  so  well  done  that  dimensions  may  be  accurately  scaled 
from  the  map  without  any  calculation.  For  small  plats, 
such  as  public  squares  and  small  parks,  50  feet  to  the  inch 
would  be  a  suitable  scale,  admitting  the  smallest  detail. 
For  larger  areas,  such  as  town  sites,  extensive  parks,  sub- 
urban resorts,  etc.,  a  scale  of  200  feet  to  the  inch  is  com- 
monly used.  The  scale  must  be  reduced  in  proportion  as 
the  area  is  increased.  Published  topographical  maps  are 
usually  made  to  a  scale  of  one  inch  to  the  mile,  admitting 
of  the  representation  of  all  towns,  villages,  farms,  woods, 
isolated  buildings,  and  every  stream  of  600  feet  in  length, 
and  every  hill  of  100  feet  in  height  and  500  or  600  feet  in 
horizontal  extent. 

On  a  scale  of  two  inches  to  the  mile,  the  various  features 
of  the  ground  can  be  clearly  and  accurately  represented. 
All  streams  of  300  feet  in  length,  every  pond  not  less  than 
50  feet  broad,  and  all  towns,  villages,  roads,  foot-paths, 
farms,  and  isolated  buildings, 

A  scale  of  six  inches  to  the  mile  is  best  for  military  pur- 
poses, admitting  of  a  complete  delineation  of  a  country.  In 
all  cases  the  character  of  the  surface  and  the  purpose  of  the 
map  should  determine  the  scale. 

1388.  Size  of  Maps. — Maps  for  use  in  the  field  may 
vary  in  size  from  18  by  24:  inches  to  24  by  30  inches.  Both 
sizes  are  suitable  for  railroad  work.  The  lines  should  be  so 
arranged  on  the  different  sheets  that  they  may  be  fitted 
together,  making  a  continuous  map  of  the  line  of  survey. 
The  sheets  should  be  numbered  in  regular  rotation,  and 
when  pinned  together  they  will  appear  as  shown  in  Fig. 
354. 

Where  possible,  arrange  the  sheets  so  that  each   curve 


810 


MAPPING. 


with  its  center  and  limiting  radii  may  come  on  the  same 
sheet.  Sometimes  this  cannot  be  done.  The  points  where 
the  different  sheets  join  on  to  each  other  should  be  fixed  by 
a  line  drawn  at  right  angles  to  the  center  line  or  radial  line 


l:^ 

/ 

A      .   '? 

^^^^^^ 

3 

o 

°f  /(( 

'i 

k     ,, 

Br 

V.                  1 

"■-J-—* 

\C^  \ 

o       III 

-■!' 

o 

L=>'«=« 

\ 

,yA 

\~^'''--i 

\^-\^ 

0 

Fig.  354. 
at  the  point  of  junction,  as  at  A  or  B.     This  simplifies  the 
work  of  fitting  the  sheets  and  greatly  promotes  accuracy. 

1389.  Lettering. — Legibility  and  uniformity  are  the 
requisites  for  good  lettering.  Ornamental  letters,  ex- 
cepting for  titles,  are  entirely  out  of  place,  and  they  are 
only  admissible  for  titles  of  very  elaborate  maps.  All  let- 
tering in  the  body  of  the  map  or  details  should  be  in 
italics.  Small  letters  should  be  two-thirds  the  height  of 
capitals,  ordinary  capitals  |  of  an  inch  in  height,  and  small 
letters  f  of  ^  or  -^^  i^^h  in  height.  Uniformity  in  spacing 
letters  is  as  important  as  uniformity  in  size.  There  is  no 
work  where  practice  is  more  essential,  if  skill  is  to  be  ac- 
quired, and  nothing  adds  more  to  the  finish  of  a  drawing 
than  good  lettering,  while  poor  and  slovenly  lettering  will 
rob  of  all  merit  an  otherwise  perfect  drawing. 

1390.  General  Instructions. — If  the  entire  map  is 
to  be  contained  on  a  single  sheet,  judgment  is  required  in 
fixing  the  direction  of  the  first  course  so  as  to  attain  that 
result.     The  points  of  the  compass  must  also  be  in  their 


MAPPING.        ■  811 

natural  order,  viz.,  North  at  the  top  of  the  map  and  South 
at  the  bottom. 

The  outline  of  the  map  will  determine  the  position  of  the 
title.  Yery  fine  lines  are  a  blemish  rather  than  a  merit,  and 
heavy  lines  are  likewise  to  be  avoided  except  when  used  for 
shading  or  boundaries.  Boundaries  of  private  property  are 
represented  by  bold,  full  lines,  and  those  of  state,  county, 
or  municipality  by  heavy  broken  and  dotted  lines.  All 
dimensions  should  be  expressed  in  figures,  and  all  impor- 
tant lines  and  objects  briefly  but  accurately  described. 


RAILROAD   LOCATION. 


1391.  Need  of  a  Railroad. — This  subject  presup- 
poses that  there  is,  beyond  a  doubt,  need,  both  present  and 
prospective,  for  the  railroad  whose  location  is  to  be  decided 
upon. 

1392.  Available  Capital.— The  first  duty  of  the 
Chief  Engineer  is  to  know  how  much  money  those  having  the 
direction  of  the  enterprise,  commonly  known  as  tJic  company, 
have  or  can  command,  as  all  subsequent  operations  will  be 
governed  by  that  fact  alone.  Having  obtained  that  infor- 
mation, he  collects  all  available  maps  of  the  country  to  be 
operated  in,  and  from  them  derives  a  general  knowledge  of 
the  mountain  ranges,  valleys,  rivers,  together  with  their 
tributaries,  and  the  location  of  all  towns  and  villages  lying 
within  that  territory,  their  relative  size  and  importance. 

1393.  Terminals. — The  terminals  or  extremities  of 
the  proposed  railroad  are  known,  and  the  first  problem  be- 
fore the  engineer  is  to  determine  the  general  route  which 
the  line  connecting  them  should  take.  A  careful  study  of 
the  maps  in  hand  will  indicate  to  him  the  different  possible 
routes  whose  comparative  merits  he  can  know  only  by  care- 
ful investigation.  The  number  of  these  possible  routes  will 
probably  be  further  reduced  by  the  location  of  certain  towns 
which  must  be  reached  for  traffic  considerations.  These 
towns  will  divide  up  the  line  into  two  or  more  sections,  each 
offering  considerable  range  in  choice  of  location,  which  in- 
dicate to  the  engineer  the  scope  of  the  country  to  be  covered 
by  the  reconnaissance. 

1394.  Important  Considerations. — The  engineer 
should  preserve  an  optimistic  habit  of  mind,  believing  noth- 
ing to  be  too  difficult  to  be  overcome,  and  fully  expecting 


814  RAILROAD   LOCATION. 

to  find  a  line  in  every  way  superior  to  that  which  had  been 
regarded  as  possible.  It  is  of  the  highest  importance  that 
he  should  regard  the  proposed  line  from  a  business  point  of 
view,  and  be  able  to  distinguish  between  what  is  commer- 
cially important  and  physically  important.  He  should  keep 
constantly  in  mind  this  vital  fact,  viz.,  that  a  line  of  rail- 
road is  built  for  the  pifrpose  of  making  money  for  its  project- 
ors; that  any  expenditure  which  will  add  proportionately  to 
the  earning  power  of  the  road  is  wise^  and  that  any  which 
will  not  is  criminal  zaaste. 

1395.  Relative  Economy. — The  engineer  must, 
however,  be  able  to  distinguish  between  wise  and  unwise 
economy.  Because  a  line  is  brought  to  sub-grade  cheaply,  it 
is  not  necessarily  economical  grading.  It  requires  an  average 
continuous  cut  and  fill  of  7  feet,  with  the  usual  proportion 
of  masonry,  to  equal  the  cost  of  the  superstructure,  i.  e., 
ties,  rails,  fastenings,  and  ballast,  while  the  cost  of  rolling 
stock,  machinery,  buildings,  etc.,  of  an  active  road,  cost 
nearly  as  much  as  roadbed  and  track  complete. 

1396.  Towns  and  Terminals. — Towns,  which  are 
always  the  main  sources  of  traffic,  and  terminals,  which, 
besides  being  sources  of  traffic,  are  the  main  points  of 
traffic  exchange,  are  considerations  of  vital  importance  to 
the  road.  No  expense  within  the  possible  reach  of  the  com- 
pany should  be  spared  in  reaching  the  heart  of  towns  and  in 
providing  the  best  traffic  facilities.  A  small  saving  in  time 
and  a  small  increase  in  comfort  will,  other  things  being 
equal,  secure  the  traffic.  Where  the  new  line  comes  into 
competition  with  old  and  favored  lines,  no  pains  which  tact 
or  ingenuity  can  devise  should  be  spared  to  induce  favor  and 
patronage.  It  is  at  such  a  juncture  that  tact  and  enterprise 
count.  No  source  of  business,  however  insignificant,  should 
be  overlooked,  and  every  point  gained  should  be  held  at  any 
reasonable  cost.  Provide  ample  terminal  grounds  at  any 
possible  cost;  with  them  a  new  road  will  have  a  hard  fight, 
while  the  lack  of  them  places  the  road  at  a  great  disadvan- 
tage from  the  first,  and  may  cause  its  ruin. 


RAILROAD    LOCATION.  815 

1397.  Comparative    Cost    of  Different    Lines. — 

In  order  that  the  engineer  may  correctly  estimate  the  com- 
parative cost  of  different  lines,  he  must  know  the  actual 
cost  of  work  of  various  kinds,  and  be  able,  from  his  exami- 
nations of  the  country,  to  properly  classify  it.  Experience 
in  the  location  and  construction  of  other  lines  will  alone 
enable  him  to  decide  between  the  comparative  merits  of  the 
different  routes. 

The  almost  universal  fault  of  engineers  is  to  underesti- 
mate cost,  a  fault  common  to  all  persons  who  are  about  to 
undertake  construction  of  any  kind.  Experienced  engineers 
make  it  a  rule  to  add  10  per  cent,  to  the  estimate  which  is 
intended  to  cover  all  possible  cost. 

1398.  Considerations  Which  Determine  the 
Route. — Traffic  and  engineering  considerations  will  usually 
reduce  the  possible  routes  to  tivo  if  not  to  one^  thus  narrow- 
ing the  field  of  operations.  The  work  of  reducing  the  traffic 
and  engineering  possibilities  of  a  section  of  country  to  their 
lozvest  terms  is  emphatically  the  work  of  the  chief  engineer, 
and  is  embraced  in  that  most  important,  though  much  mis- 
understood, term,  viz.,  the  reconnaissance.  Let  the  young 
engineer  keep  prominently  before  his  mind  that  the  largest 
half  of  a  railroad  survey  is  the  reconnaissance.  Let  him 
ponder  well  the  varied  interests  and  problems  which  con- 
front him,  and  let  him  know  his  country  before  he  drives  a 
stake.  This  knowledge  can  be  had  only  by  hard  work  and 
a  good  deal  of  it. 

RECONNAISSANCE. 

1399.  General  Directions. — Having  provided  him- 
self with  the  best  available  map  of  the  section  immediately 
in  hand,  an  aneroid  barometer,  and  a  guide  who  is  familiar 
with  the  section,  the  engineer  is  ready  for  a  start.  He 
should  avoid  highways  if  he  is  to  acquire  the  knowledge  he 
is  seeking,  as  they  give  the  traveler  an  erroneous  impres- 
sion of  the  character  of  the  surrounding  country.  He  un- 
consciously believes  because  the  "  walking  is  good  "  that  the 


816  RAILROAD    LOCATION. 

surrounding  country  is  smooth  and  tractable,  and  obstacles 
to  railroad  building  few  and  insignificant.  On  the  other 
hand,  by  taking  a  cross-country  route,  he  will  be  likely  to 
exaggerate  those  obstacles,  simply  because  they  have  im- 
peded his  travel.  All  experience  goes  to  prove  that  in 
America,  at  least,  the  railways  avoid  the  highways;  not 
through  the  intent  of  the  engineer,  but,  as  it  were,  in  silent 
condemnation  of  the  incapacity  of  those  who  directed  their 
building.  The  engineer  should  keep  constantly  in  mind 
that  his  examinations  are  not  to  be  confined  to  the  strip  of 
country  within  his  immediate  vision,  but  are  to  cover  a 
range  of  several  miles  on  either  side  of  his  line  of  march. 
Much  information  he  can  obtain  from  his  guide;  more  he 
must  find  out  for  himself — taking  nothing  for  granted  where 
a  doubt  is  raised.  Very  often  an  apparent  obstruction 
which,  did  it  really  exist,  would  effectually  bar  the  way, 
will  disappear  upon  a  careful  inspection  of  the  country,  or 
at  the  worst  prove  an  insignificant  obstacle  compared  to 
those  already  passed.  Obstacles  to  travel  are  not  neces- 
sarily obstacles  to  railway  building.  Narrow  defiles,  ob- 
structed by  boulders,  underbrush,  and  timber  will,  when 
cleared,  appear  comparatively  smooth. 

1400.  Use  of  the  Hand  Level.— The  hand-level  is 
of  the  greatest  value,  and  should  be  in  constant  use.  The 
unaided  eye  is  of  little  use  in  estimating  comparative 
elevations.  The  hand  level  determines  relative  heights, 
constantly  affording  needed  information  and  saving  much 
time,  which,  without  it,  would  be  spent  in  useless  tramping. 

1401.  Keeping  Notes. — A  careful  record  should  be 
kept  of  all  streams  encountered;  their  direction,  and  of 
what  larger  streams  they  are  tributaries. 

The  sizes  of  different  streams  in  the  same  section,  to  a 
certain  degree,  determines  their  relative  elevations.  The 
larger  the  stream  the  lower  its  elevation.  The  velocity  of 
its  current,  in  a  measure,  indicates  the  grade  of  a  stream, 
though  a  fall  which  would  make  a  torrent  of  a  river  Avould 
give  but  a  feeble  current  to  a  shallow  stream.     The  recon- 


RAILROAD   LOCATION.  817 

naissance  should  cover  a  complete  section  of  the  proposed 
line  before  the  work  of  actual  survey  is  commenced,  though 
it  is  not  to  be  considered  as  complete  until  the  final  location 
is  fixed. 

1402.     Deceptive  Appearances  of  Country. — The 

natural  eyesight  is  easily  deceived,  and  rarely  gives  to 
objects  their  true  relative  proportions..  Two  reasons  for 
this  deception  are  the  following: 

First,  the  eye  foreshortens  the  distance  in  an  air  line,  and 
exaggerates  a  lateral  offset.  This  fact  is  illustrated  by 
Fig.  355,  in  which  let  the  points  A  a.ndB,  which  are  10,000 


ft.  apart,  be  in  an  air  line  between  two  towns,  and  suppose 
this  line  to  cross  a  ridge,  the  highest  point  of  which  is  at  C, 
and  that  the  ridge  flattens  out  at  D,  2,000  feet  from  C,  the 
middle  point  of  A  B.  To  the  inexperienced,  the  offset  C  D, 
as  seen  on  the  ground,  will  be  greatly  exaggerated,  appear- 
ing to  be  fully  one-half  the  straight  line  A  B,  and  the  con- 
viction will  follow  that  in  passing  from  A  to  B  hy  way  of  C, 
not  only  will  a  great  deal  of  curvature  be  introduced,  but 
the  length  of  the  line  will  be  so  greatly  increased  over  that 
of  A  B  as  to  make  a  careful  consideration  of  the  route  out 
of  the  question;  even  though  the  line  A  Z>' should  require 
steep  grades  and  a  heavy  cut  at  C.  This  exaggeration  is 
apparent  when  we  find  by  calculation  that  the  distance  from 
A  to  B  hy  way  of  D  is  only  770.33  ft.  greater  than  the 
direct  line  between  A  and  B.  This  illusion  of  the  eye  ex- 
plains the  aversion  to  sivinging  the  line,  too  common  among 
engineers,  and  the  undue  importance  attached  to  good 
alineinent.  The  chances  are  four  to  one  that  the  line 
A  D  B  is  immensely  superior  to  the  line  A  B,  both  in  cost 


818 


RAILROAD    LOCATION. 


and  grades,  while  the  increase  in  distance  of  the  line  A  D  B 
over  the  line  A  B  vs,  less  than  8  per  cent. 

Frequently  a  deflection,  which  will  not,  in  reality,  add 
more  than  15  per  cent,  to  the  length  of  a  line,  will  appear 
to  double  it,  and  the  deplorable  mistake  is  often  miade  of 
adopting  the  air  line,  even  though  it  cost  25  per  cent,  in 
excess  of  what  the  deflected  line  would  cost. 

Second,  the  eye  exaggerates  the  sharpness  of  projecting 
points  and  spurs  and  the  degree  of  curvature  necessary  to 
pass  around  them.  All  slopes  when  looked  at  from  in  front, 
are  exaggerated  by  the  eye.  Few  mountains  have  slopes 
exceeding  1^  to  1  or  33^°,  yet  the  eye  will  estimate  such  a 
slope  at  from  45°  to  50°. 

In  running  the  line  A  B  C  D,  Fig.  356,  the  engineer,  if  he 
were  to  accept  his  natural  estimate  of  the  angles  at  B  and  C, 


Fig.  356. 

would  make  the  angle  at  C  about  twice  as  large  as  the  angle 
at  B;  even  though  he  had  walked  over  the  line.  The  reason 
for  this  is  that  while  standing  at  any  point  on  the  line  B  C, 
his  view  of  the  line  C  D  is  cut  off  by  the  profile  £  C  of  the 
hill  in  front,  and,  in  spite  of  himself,  the  unseen  will  be 
distorted  and  invariably  magnified. 

Nowhere  is  the  proverb,  "appearances  are  deceiving," 
so  true  as  in  an  apparently  smooth  or  gently  rolling  country. 
The  undulations  are  so  gradual  that  their  aggregate  is  rarely 
suspected.  Abundant  experience  goes  to  prove  that  an  air 
line  in  such  a  country  is  only  possible  at  the  cost  of  heavy 
grades  and  long  and  heavy  cuts  and  fills.  To  avoid  them, 
frequent  deflections  must  be  made,  introducing  curvature 
in  proportion,  though  the  increase  in  length  of  line  is  in  no 


RAILROAD   LOCATION. 


819 


degree  proportional  to  the  saving  in  cost  of  construction  and 
operation. 

1403.  Discredit  All    Unfavorable    Reports. — An 

unfavorable  report  of  a  locality,  more  than  any  other,  should 
challenge  a  careful  examination.  The  inexperienced  are 
easily  daunted  by  obstacles  which  are  really  insignificant. 
A  section  heavily  timbered  and  covered  with  boulders,  and 
appearing  to  them  as  forbidding  in  the  extreme,  would  likely 
show  an  alinement  and  grades  incomparably  better  than  the 
line  of  their  choice.  In  reconnaissance  it  is  the  unexpected 
which  happens,  and  the  line  which  appears  least  promising 
will  often  prove,  by  far,  the  best. 

1404.  Choice  of  Lines. — Never  believe  that  only  one 
line  is  possible.     There  are  always  two,  and  generally  sev- 


FIG.  357. 


eral.     The  important  question  is,  which  line  is  the  best,  and 


820  RAILROAD   LOCATION. 

that  is  the  one  to  settle  upon.  The  following  instance  well 
illustrates  this  point.  The  facts  in  the  case  are  shown  in 
Fig.  357.  The  line  had  followed  the  river  A  B  for  several 
miles,  keeping  a  uniform  grade  of  about  30  feet  per  mile.  It 
became  necessary  to  leave  the  river  valley  and  climb  a  ridge 
in  order  to  reach  a  town  lying  in  another  valley.  The  entire 
country  was  thickly  covered  with  timber  and  undergrowth, 
and  consisted  of  abrupt,  irregular  hills,  called  hog-backs. 
The  brook  C  was  known  to  the  engineer,  who  endeavored  to 
trace  it  to  its  junction  with  the  river,  but  the  brook  lost  it- 
self in  a  cedar  swamp  at  Z>,  and  it  was  impossible  to  find  the 
outlet.  After  repeated  effort  to  find  the  outlet  and  encoun- 
tering each  time  the  ridge  E  which  lay  between  the  river  and 
the  valley  D  C,  he  continued  the  line  up  the  river,  crossing 
it  at  B,  where  a  precipitous  ledge  prevented  further  progress 
along  the  river,  and  crossing  the  neck  of  land  /%  and  the 
river  at  G,  commenced  to  climb  the  ridge  doubling  about 
the  sharp  headland  at  //, .  and  then  swinging  backwards, 
making  the  line  K  L  with  a  heavy  fill  at  M.  This  seemed 
the  only  possible  line,  but  it  was  so  rough  and  crooked  that 
the  engineer  determined  to  make  another  trial.  He  spent 
two  days  in  hard  tramping  during  a  continual  downpour  of 
rain,  discovering  the  narrow  opening  at  N  through  which 
the  brook  found  its  way.  He  also  found  the  brooks  /*and  Q, 
and  blazed  a  line  through  from  E  \.o  K.  A  line  was  then 
run,  following  this  course  with  the  most  satisfactory  results, 
saving  two  river  bridges  and  three  miles  in  distance,  though 
getting  through  the  ridge  at  E  entailed  a  heavy  cut.  The 
railroad  company  was  opposed  to  any  further  investigation 
after  the  completion  of  the  first  line,  as  a  month  of  hard 
work  had  been  expended  upon  it.  Yet  the  saving  in  first 
cost  accomplished  by  the  adoption  of  the  second  line  over 
the  first  would  have  paid  the  engineering  expenses  of  the 
entire  line  of  100  miles.  In  general,  a  better  line  than  the 
one  already  in  hand  can  be  found  by  looking  for  it. 

1405.     Advantages    of    Valley    Lines. — Wherever 
possible,  stick  to  the  valleys.     Bottom  lands,  though  low- 


RAILROAD   LOCATION.  821 

lying,  are  generally  above  flood  line,  or,  if  below  it,  are  only 
covered  by  back-water,  else  they  would  have  been  long  since 
washed  away.  Though  a  crooked  channel  may  necessitate 
frequent  and  sharp  curves,  yet  they  are  more  than  compen- 
sated for  by  the  low  grades  fixed  by  that  channel.  As  fre- 
quently happens,  the  bends  in  the  channel  are  caused  by 
projecting  heads  of  hills.  These  sharp  and  often  rocky 
points  usually  require  but  short  cuts,  and  furnish  the  best 
of  material  for  the  adjacent  embankments. 

Notes  should  be  kept  of  all  important  information  gained. 
Points  where  two  promising  lines  diverge  should  be  so 
marked  as  to  be  readily  recognized. 

The  reconnaissance  being  completed  and  all  economical 
and  topographical  questions  settled,  the  next  duty  of  the 
engineer  is  the  preliminary  survey.  The  party  should  be 
organized  and  all  ready  for  service  the  moment  the  recon- 
naissance and  general  route  is  decided  upon. 

1406.  Organization  of  Party. — The  size  of  the 
party  will  depend  upon  the  character  of  the  country  in  which 
the  work  is  to  be  done.  If  thickly  settled,  smaller;  if  thinly 
settled,  larger. 

A  well-equipped  party  in  ordinary  country  should  number 
sixteen  men,  as  follows:  The  transit  party,  comprising 
chief  of  party,  transitman,  two  chainmen,  three  axmen, 
one  stakeman,  and  one  back  flagman;  the  level  party,  com- 
prising the  leveler,  rodman,  and  one  axman,  and  the  topo- 
graphical party,  comprising  the  topographer  and  two  assist- 
ants. The  last  to  be  named,  though  not  the  last  in  point 
of  importance,  is  the  teamster,  who  should  be  provided  with 
a  strong,  active  team,  and  spring  wagon  that  will  not  break 
down.  It  is  a  most  wasteful  economy  to  require  a  party  to 
walk  from  two  to  five  miles  before  commencing  work,  and 
then  to  quit  work  in  time  to  make  another  long  tramp  be- 
fore reaching  shelter.  A  chief  of  party  who  does  not  know 
the  necessity  for  a  team  and  insist  upon  having  it,  is  not  fit 
for  the  work  in  hand.  No  company  will  refuse  to  provide 
it,  if  the  matter  be  properly  presented,  yet  many  parties  are 


822  RAILROAD    LOCATION. 

deprived  of  this  important  part  of  the  outfit.  If  the  party 
are  living  in  camp,  a  team  is  an  absolute  necessity  for 
moving  the  camp,  which  will  be  done  at  least  once  a  week, 
and  usually  once  in  three  or  four  days. 

1407.  Caqip  Outfit. — For  camp  work  the  following 
outfit  will  be  necessary: 

Two  wall  tents  with  flies,  or  extra  roofs,  for  the  accom- 
modation of  the  men,  and,  if  the  work  is  to  be  carried  on 
during  the  winter  season,  a  tent  must  be  provided  for  the 
team ;  a  sheet-iron  stove  and  provision  chest  for  the  com- 
missary ;  a  cook  who  can  prepare  wholesome  food  and  plenty 
of  it,  and  keep  himself  and  belongings  clean  and  orderly;  a 
drafting  table,  which  is  nothing  more  than  a  large  draw- 
ing board,  a  straight-edge  and  triangles,  an  ordinary  pocket 
case  of  drafting  instruments,  together  with  a  beam  com- 
pass, will  answer  for  all  preliminary  drafting.  Drawing 
and  profile  paper,  note  books,  etc.,  are  carried  in  a  camp 
chest.  Each  man  provides  his  own  bedding,  which  consists 
of  blankets  alone. 

The  field  instruments  will  comprise  the  following,  viz. : 
A  surveyor's  compass,  plain  transit,  and  transit  poles,  Y  level 
and  Philadelphia  leveling  rod,  aneroid  barometer,  clinom- 
eter, slope  rod,  chain,  axes,  marking  crayons,  tacks,  and 
stake  straps  about  the  width  and  length  of  ordinary  trunk 
straps.  A  supply  of  stakes  should  be  kept  constantly  on 
hand.  If  possible,  have  these  of  light,  well-seasoned  wood 
(pine  is  best)  and  of  the  following  dimensions:  Length 
2  ft.  6  in.,  width  2  in.,  thickness  ^  in.,  and  planed  on  one 
side  so  as  to  admit  of  easy  and  plain  numbering.  Special 
conditions  may  require  additional  equipment,  but  the  above 
outfit  will  meet  all  ordinary  requirements. 

1408.  The  Compass  for  Preliminary  Work. — If 

the  section  be  comparatively  free  from  iron  deposits,  the 
preliminary  line  should  be  run  with  the  compass,  for  in  spite 
of  small  inaccuracies  in  alinement  due  to  errors  in  reading 
the  needle,  the  average  accuracy  of  a  number  of  readings 
will  closely  approximate    to  those    read  with    the    transit 


RAILROAD   LOCATION.  823 

vernier.  The  comparative  advantages  of  compass  and  tran- 
sit for  preliminary  railroad  surveys  was  discussed  in  Art. 
1217.  Suffice  to  say,  that  where  the  conditions  warrant 
it,  the  compass  is  always  the  more  economical  and  expedi- 
tious instrument.  If,  however,  iron  exists  in  quantities 
sufficient  to  hinder  the  perfect  freedom  of  the  magnetic 
needle,  the  compass  must  be  discarded  for  the  transit,  with 
the  injunction  to  never  record  an  angle  without  first  check- 
ing it ;  and  after  recording,  read  the  angle  a  second  time. 
The  assurance  of  accuracy  is  worth  many  times  the  labor 
and  care  of  checking  work. 


FIELD  WORK. 
1409.  The  Starting  Point.— In  general,  the  start- 
ing point  of  the  survey  will  be  at  an  extremity  of  one  of  the 
sections  into  which  the  proposed  line  is  divided.  If  it  is  to 
connect  with  some  already  existing  line,  a  point  on  that  line 
is  taken;  if  not,  a  street  line  or  some  other  fixed  boundary 
is  chosen  and  the  line  tied  into  it.  The  chief  of  party  ac- 
companied by  a  flagman,  goes  ahead  and  fixes  the  points 
where  the  angles  are  to  be  taken.  The  flagman  carries,  be- 
sides the  transit  pole,  an  ax  for  making  plugs,  one  of 
which  he  drives  flush  with  the  ground  at  every  transit 
point.  A  galvanized  tack,  or,  better  still,  a  small  galvan- 
ized nail,  is  driven  in  the  center  of  the  plug  and  the  transit 
pole  (flag)  held  on  the  point  while  the  transitman  reads  the 
angle.  A  point  having  been  fixed,  and  the  flag  set  up,  the 
transitman  measures  the  angle  between  the  boundary  at 
Station  0  and  the  first  course.  The  angle  and  bearing  of  the 
line  being  recorded,  the  transitman  walks  rapidly  to  the 
point  where  the  flag  is  standing  and  sets  up  the  instrument 
at  that  point.  The  head  flagman  should  carry  about  a  dozen 
pieces  of  red  flannel  to  be  used  as  targets.  As  soon  as  a 
transit  point  is  set  and  the  transitman  has  signaled  that  the 
angle  is  read,  the  flagman  should  tie  a  piece  of  target  flan- 
nel to  a  light  stake  of  about  the  same  length  as  the  transit 
pole,  and  plant  the  pole  firmly  in  line  directly  behind  the 


824  RAILROAD   LOCATION. 

plug  or  transit  point.  This  affords  the  chainman  a  good 
target  for  liJiing  in,  and  allows  the  flagman  to  join  the  chief 
of  party  who  has  gone  ahead  to  select  another  transit  point. 
The  transit  being  set  up,  a  backsight  is  taken  to  a  flag  held 
at  the  starting  point  (Station  0).  The  bearing  is  then 
checked  and  the  angle  turned  to  the  next  point  ahead.  The 
chainmen  having  come  up  with  the  transit,  they  report  the 
number  of  the  station  of  the  transit  point  to  the  transitman, 
who  records  it  in  the  transit  book.  He  then  directs  the 
chainman  on  the  next  course,  reads  the  forward  angle  and 
records  it  together  with  the  bearing  of  that  course,  and  then 
moves  up  to  the  next  transit  point. 

1410.  The  Level  Party. — The  level  party  follows 
the  transit  party  as  closely  as  possible.  The  levels  of  the 
proposed  line  and  the  line  with  which  it  is  to  connect  should 
be  referred  to  the  same  datum  plane,  so  as  to  secure  a  con- 
tinuous profile;  especially  if  the  levels  of  the  established 
line  are  referred  to  the  sea  level.  If  such  a  base  is  not 
practicable,  an  elevation  for  the  starting  point  must  be  as- 
sumed, but  of  such  a.  height  as  will  bring  all  elevations  of 
the  proposed  line  above  the  assumed  datum  plane. 

In  case  the  country  is  wooded,  with  the  added  hindrance 
of  thick  underbrush,  the  transit  party  will  of  necessity  move 
slowly,  and  the  level  party  will  consequently  have  much 
spare  time  on  their  hands.  They  should  provide  themselves 
with  profile  paper  and  keep  the  profile  platted  as  the  work 
progresses. 

1411.  Bench  Marks. — Bench  marks  are  established 
at  intervals  of  from  1,000  to  1,500  feet,  according  as  the  line 
is  rough  or  smooth.  At  every  stream  which  the  line  crosses 
the  elevation  of  the  surface  of  the  water  and  of  the  bed  of 
the  stream  should  be  taken.  If  there  are  any  marks  indica- 
ting the  elevation  of  high  water,  a  rod  reading  should  be 
taken  at  such  point  and  a  record  made  of  it. 

141 2.  The  Topographical  Party. — The  topograph- 
ical party  follows  the  level  party,  though  their  rate  of  progress 
will  be  more  uncertain  than  either  of  the  parties  preceding 


RAILROAD   LOCATION.  825 

them.  Where  the  slopes  are  uniform,  they  need  not  be 
taken  oftener  than  every  third  or  fourth  station.  If,  how- 
ever, the  country  is  broken  and  rough,  it  may  be  necessary 
to  take  them  .at  each  hundred  feet,  and  with  great 
minuteness. 

1413.  Office  Work. — At  the  conclusion  of  each  day's 
work,  the  field  notes,  both  transit  and  level,  are  carefully 
checked,  and  a  plat  of  the  line  is  made,  either  by  tangents 
or  by  latitudes  and  departures,  carefully  marking  the  cross- 
ings of  streams  and  highways,  and  noting  any  important 
point  which  would  enable  the  chief  engineer  to  readily 
locate  any  particular  section  of  the  line.  Where  the  coun- 
try is  smooth  the  line  may  be  platted  to  a  scale  of  400  feet 
to  the  inch.  Rough  parts  of  the  line  may  not  exceed  a 
scale  of  200  feet  to  the  inch,  and  where  difficult  country  is 
encountered,  involving  detailed  topographical  maps,  a  scale 
of  100  feet  to  the  inch  is  advisable.  Plat  the  line  on  sheets 
24'  X  30'  in  size,  numbering  them  in  regular  order,  each 
sheet  containing  a  part  of  the  line  on  the  immediately  pre- 
ceding sheet,  so  that  by  matching  and  pinning  them 
together,  there  may  be  had  a  continuous  map  of  the  line. 
So  arrange  the  line  on  the  different  sheets  that  when  the 
paper  location  is  made  they  shall  contain  as  many  curve 
centers  as  possible. 

The  topographer  will  do  his  proportional  share  of  the 
work,  which  will  consist  mainly  in  a  detailed  explanation  of 
the  notes  of  the  day's  work  to  the  draftsman,  whose  princi- 
pal work  is  the  contour  maps.  The  leveler  will  plat  the 
day's  levels  on  the  continuous  profile  kept  in  the  office,  the 
rodman  reading  the  notes.  This  profile  will  contain  as  full 
information  as  possible,  especially  relating  to  highways  and 
watercourses. 

Some  engineers  prefer  to  wait  for  a  rainy  day  in  which  to 
do  the  office  work,  but  more  make  it  an  invariable  rule  to 
plat  each  night  the  work  of  the  day.  This  practice  enables 
the  chief  of  party  to  have  a  complete  record  of  his  work 
always  ready  for  the  inspection  of  the  chief  engineer,  who 


626 


RAILROAD    LOCATION. 


is  liable  to  appear  at  any  time.  If  he  is  his  own  chiefs  per- 
sonal interest  in  the  work  would  warrant  him  in  making 
such  a  rule.  Notes  which  are  platted  when/V^.f//  are  always 
of  more  value  than  when  stale,  and  the  daily  office  work 
unites  the  different  parties  which  are  separated  during  the 
day,  sustaining  a  common  interest  in  the  work.  If  the  con- 
tour maps  are  to  keep  pace  with  the  survey,  the  draftsman 
must  be  an  expert.  Each  day  he  plats  the  work  of  the  pre- 
ceding day,  and  under  the  direction  of  the  topographer, 
every  point  is  covered. 

1414.     Spur  Lines. — At  certain  points  of   the  main 
line,  two  and  sometimes  three  different  routes  will  present 


Fig.  368. 


RAILROAD   LOCATION.  827 

themselves  for  reaching  another  point  of  that  line,  and  re- 
quire the  running  of  spur  lines  to  determine  the  most  advan- 
tageous route.  The  main  line  being  run,  the  spur  lines  are 
tied  into  it,  designating  them  by  different  letters,  as  liney^, 
line  B^  etc.  The  comparative  advantage  of  the  different 
alinements  will  show  themselves  in  the  plat.  Their  com- 
parative profiles  are  commonly  shown  by  platting  them  in 
different  colors.  A  case  requiring  spur  lines  is  shown  in 
Fig.  358.  Here  the  general  direction  of  the  main  line  is 
C  D  E  F,  D  being  the  point  where  the  spur  lines  A  and  B 
diverge  from  the  main  line,  and  E  where  they  again  unite. 
It  will  be  evident  from  an  inspection  of  the  map  that 
the  main  line  is  superior  to  both  the  spur  lines  in  point 
of  alinement.  Their  comparative  lengths  are  already 
known.  With  the  comparative  profiles  before  the  engineer, 
he,  knowing  the  nature  of  the  ground  on  the  different  lines, 
will  have  no  difficulty  in  making  a  judicious  choice  of  lines. 
Sometimes  where  the  merits  of  the  different  lines  are  nicely 
balanced,  it  becomes  necessary  to  locate  on  two  lines  and 
base  a  decision  upon  actual  estimate  of  cost  of  construction. 

1415.  Gradients. — The  preliminary  survey  having 
been  completed,  a  careful  study  of  the  profiles  will  enable 
the  chief  engineer  to  establish  a  gradient  whose  maximum 
will  limit  the  train  loads  passing  over  it. 

The  character  of  the  expected  traffic  will  greatly  modify 
this  maximum.  If  the  road  is  to  do  a  passenger  business 
principally,  the  gradient  may  be  raised,  but  if  the  bulk  of 
the  business  is  to  be  freight,  the  gradient  must  bcplaced  at 
the  lowest  possible  limit  which  the  finances  of  the  company 
and  the  nature  of  the  country  will  permit. 

Should  all  the  heavy  grades  occur  on  a  short  section  of  the 
line,  it  may  be  policy  to  mass  them  within  the  smallest  pos- 
sible limits  and  proportionately  reduce  the  gradient  of  the 
remainder  of  the  line.  In  such  an  arrangement  of  grades, 
an  assistant  engine  would  be  used  on  the  summit  section, 
and  so  cover  the  entire  line  without  any  change  of  train 
loads. 


828 


RAILROAD   LOCATION. 


1416.  Curvature. — There  is  no  absolute  rule  for 
limiting  curvature.  The  approximate  limit  will  depend 
upon  the  topography  of  the  country  and  upon  the  character 
of  the  expected  traffic,  a  freight  traffic  admitting  a  higher 
and  a  passenger  traffic  requiring  a  lower  degree  of  curvature. 
For  all  ordinary  traffic  conditions,  i.  e.,  where  freight  and 
passenger  traffic  will  be  about  equal,  the  invariable  rule  is 
use  such  curves  as  zvill  best  conform  to  the  existing 
topographical  conditions. 

Any  curve  up  to  10  degrees  will  be  no  obstacle  to  a  speed 
of  30  miles  per  hour,  the  average  speed  of  passenger  trains. 
This  affords  a  range  in  curvature  which  will  meet  the 
requirements  of  most  localities. 

Curvature  is  no  blemish  to  a  line,  if  it  secures  the  great 
advantages  of  low  gradients  and  moderate  cost.     At  points 


Fig.  359. 


where  moderate  curves  are  possible  only  at  great  cost,  it  is 
often  a  wise  policy  to  build  a  temporary  line,  using  sharp 
curves,  and  put  off  the  expensive  work  until  the  financial 
strength  of  the  company  warrants  its  undertaking. 


RAILROAD    LOCATION.  8'29 

An  instance  where  a  temporary  line  is  expedient  is  shown 
in  Fig.  359.  Here  the  track  follows  the  windings  of  a  stream 
in  a  narrow  valley,  whose  sides  are  steep  and  rough.  Unless 
the  company  is  financially  strong,  it  will  be  much  better 
policy  to  build  the  line  A  B  C  D  £,  using  curves  as  high  as 
15°,  and  reducing  cost  to  a  minimum,  than  to  build  the  line 
A  F  B,  giving  a  single  curve  of  G°,  but  requiring  a  heavy 
rock  cut  at  /%  or  perhaps  a  tunnel  at  that  point.  The  line 
A  F  £  is  always  possible,  and  when  the  road  has  built  up  a 
paying  traffic  and  finances  are  easy,  the  cut  or  tunnel  at  F 
can  be  made  without  interfering  in  any  way  with  traffic,  and, 
in  all  probability,  at  much  better  prices  than  when  the. 
temporary  line  was  built. 

The  question  of  gradients  being  decided,  a  preliminary 
profile  is  made,  which  will  serve  as  a  basis  for  a  paper 
location. 

1417.  A  Paper  Location. — The  paper  location  is 
substantially  the  one  which  takes  permanent  form  in  the 
final  or  located  line.  It  is  laid  down  on  the  contour  maps, 
which  contain  all  the  information  accumulated  by  the  pre- 
ceding surveys.  The  grade  for  each  station  is  taken  from 
the  preliminary  profile  and  marked  on  the  contour  maps 
opposite  the  corresponding  station.  This  is  readily  done,  as 
the  contours  are  but  five  feet  apart,  and  intermediate  eleva- 
tions can  easily  be  estimated.  These  grade  points  are  com- 
monly marked  by  small  red  dots  enclosed  in  small  circles  of 
the  same  color,  and  show  where  the  plane  of  the  grade 
would  cut  the  surface  of  the  ground.  A  piece  of  fine  thread 
is  then  stretched,  covering  as  many  of  these  points  as  pos- 
sible, and  a  pencil  line  drawn  in  place  of  the  thread.  This 
pencil  line  will  locate  a  tangent  on  the  map.  In  the  same 
way  any  number  of  tangents  may  be  located. 

A  set  of  office  curves  will  be  of  great  assistance  in  fitting 
curves  to  the  tangents,  the  curves  like  the  tangents  fol- 
lowing the  grade  line  as  nearly  as  possible.  Having 
determined  the  degrees  of  curve  uniting  the  tangents,  the 
intersection    angles    are    calculated   by   tangents  and  the 


830 


RAILROAD   LOCATION. 


Fig.  360. 


tangent  distances  accu- 
rately scaled  from  the 
intersection  points. 

1418.  Field  Notes 
from  the  Paper  Lo- 
cation.— In  taking  notes 
from  the  paper  location 
for  actual  field  work,  the 
points  of  curve  and  points 
of  tangent  should  be  care- 
fully referred  to  fixed 
points  in  the  preliminary 
line  (either  stakes  or 
plugs,  the  latter  are  pref- 
erable) so  that  if,  upon 
the  completion  of  any 
curve,  the  following  tan- 
gent does  not  take  the 
position  prescribed  for  it 
in  the  notes,  it  may  be 
stvnng  into  that  position. 
It  is  impossible,  especial- 
ly in  a  rough  country,  to 
make  the  actual  measure- 
ments agree  with  the  cal- 
culated measurements, 
hence  small  inaccuracies 
need  cause  no  concern. 

The  platting  of  a  paper 
location  is  illustrated  in 
Fig.  300.  Here  the  grade 
of  the  line  is  determined 
by  the  grade  of  the  stream, 
which  it  closely  follows. 
The  grade  averages .  5  per 
cent.  The  preliminary 
line  is  shown  dotted,  and 


RAILROAD    LOCATION.  831 

the  located  line  is  drawn  full.  Let  the  grade  for  Sta.  1  be  11.0 
feet.  The  grade  for  Sta.  2  will,  therefore,  be  11.0  feet  plus. 5 
foot,  or  11.5  feet.  The  grade  for  Sta.  3  will  be  11. 5 +  .5, 
or  12  feet.  By  the  same  process  we  find  the  grade  for  each 
of  the  stations  given  in  the  plat.  The  grade  for  each  station 
is  then  marked  on  the  contour  map  opposite  the  correspond- 
ing station  of  the  preliminary  line  by  a  small  dot  enclosed 
in  a  circle.  Straight  lines  A  B  and  C  D,  which  are  to  form 
tangents  in  the  paper  location,  are  then  drawn,  covering  as 
many  of  these  small  circles  as  may  be,  and  produce,  until 
they  intersect  at  E.  The  line  ^  ^  is  then  produced  to  F, 
making  E  F  =  300  feet  or  any  other  convenient  length  of 
radius  suitable  for  measuring  the  intersection  angle  by  its 
tangent.  At  /^  erect  the  perpendicular  F  G,  which  will 
be  the  tangent  of  the  intersection  angle  F  E  G.  Meas- 
uring F  G  hy  scale  F  G  =  140  feet,  though  by  calculation 
139.89  feet.  Dividing  140  by  300  we  have  a  quotient  of 
.4667  =  tan  25°.  We  find  By  trying  different  curves  that 
an  8°  curve  will  most  nearly  cover  the  grade  points  between 
the  tangents  A  B  and  C  D.  From  formula  9 1 , 7"  =  /?  tan  \  I 
(Art.  1251),  we  find  the  tangent  distance  =  158. 9  feet. 
Scaling  from  the  intersection  point  E  on  both  tangents  this 
distance  we  locate  the  P.  C.  and  P.  T.  The  station  of  the 
P.  C.  we  determine  by  scaling  from  the  P.  T.  of  the  last 
curve.  The  station  of  the  P.  T.  is,  of  course,  found  by, 
calculation. 

1419.  Paper  Location  Profile. — A  profile,  called  a 
paper  location  proflle,  is  made  from  elevations  taken 
from  the  contour  map  at  each  station  of  the  paper  location, 
and  a  grade  line  drawn  on  it  which  should  be  substantially 
that  of  the  final  location,  and  if  the  preliminary  work  has 
been  thoroughly  done,  the  discrepancy  will  be  but  slight. 

1420.  Actual  Location. — The  location  party  has  the 
same  organization  as  the  preliminary  party,  excepting  the 
topographer  and  his  assistants.  Their  work  is  supposed  to 
be  completed.  The  chief  of  party  carries,  besides  the  notes 
of  the  location,  which  is  to  be  run  in  on  the  ground^  the  map 


832  RAILROAD    LOCATION. 

covering  the  section  immediately  in  hand,  as  not  infre- 
quently it  is  necessary  to  slightly  modify  the  paper  location. 
He  will  need  in  addition  a  short  scale  and  compass  carrying 
a  pencil  point. 

Where  the  country  is  open,  it  is  good  practice  to  locate 
the  tangents  by  offsets  from  the  preliminary  line  and  make 
the  intersections  on  the  ground ;  but  if  the  ground  is  covered 
with  brush  or  timber,  the  paper  location  must  be  strictly 
followed,  and  the  results  will  generally  fulfil  all  reasonable 
expectations. 

PROBLEMS   IN  LOCATION. 

1421.  Problems  in  Location. — The  tangents  being 
fixed  in  the  paper  location,  the  purpose  is  to  so  fix  the  point 
of  curve,  the  P.  C,  that,  the  curve  being  run,  its  tangent 
shall  coincide  with  the  following  tangent  as  laid  down  in  the 
paper  location.  Frequently,  the  actual  tangent  fails  to 
coincide  with  the  theoretical  tangent,  in  which  case  it  must 
be  swung-  into  place.  Sometimes  the  tangents  not  only  fail 
to  coincide,  but  form  an  angle  with  each  other,  in  which 
case  the  central  angle  of  the  curve  must  be  either  increased 
or  diminished,  as  the  case  demands.  These  modifications 
of  the  paper  location  give  rise  to  the  following  problems, 
which  will  cover  all  ordinary  cases: 

1422.  Problem  I. — To  change  the  P.  C.  of  a  curve  so 
that  the  curve  shall  terminate  in  a  tangent  parallel  to  a 
given  tangent  and  at  a  given  distance  from  it: 

Let  A  />',  Fig.  3G1,  be  a  curve  terminating  in  the  tangent 
B  C,  and  it  is  required  to  change  the  P.  C.  of  the  curve 
from  A  to  A' ,  so  that  it  shall  terminate  in  a  tangent  B'  C 
parallel  to  B  C  and  at  a  fixed  distance  from  it. 

The  angle  B  B'  D  =  I,  the  angle  of  intersection  of  the 
tangents. 

We  have  sin  B  B'  D  =  -rm,  whence  B  B'  =  —. — ,. 
B  B  sm  / 

B  B'  ■=  O  O'  =  A  A\  the  required  distance  to  move  the 
P.  C.  of  the  curve  either  backwards  or  forwards,  according 


RAILROAD    LOCATION. 


833 


as  the  required   tangent  is  within   or  without    the   given 
tangent. 

Substituting  A  A'  ior  B  B'  we  have  A  A'  =  -. — j. 

In  the  figure  the  required  tangent  is  within  the  given 


Fig.  361. 

tangent.     Let  the  intersection  angle  be  68°  and  the  distance 

40 
B  D  =  iO  feet.     Sin  G8°  =  .92718,  whence  A  A'  =  —z^^  = 

43.14  feet. 

That  is,  the  P.  C.  of  the  required  curve  must  be  moved 

backwards  43.14  feet  from  the  P.  C.  of  the  given  curve. 
• 

1 423.  Problem  II. — To  change  the  point  of  compound 
curvature,  the  P.  C.  C,  so  that  the  second  curve  shall  ter- 
minate in  a  tangent  parallel  to  a  given  tangent,  and  at  a 
given  distance  from  it. 

Case  I.  When  the  second  curve  is  of  shorter  radius  than 
the  first  curve: 

Let  A  B  D,  Fig.  362,  be  a  compound  curve  terminating 


834 


RAILROAD    LOCATION. 


in  the  tangent  D  H,  and  let  it  be  required  to  change  the 

P.  C.  C.  from  B  to  some 
point  E,  so  that  the  curve 
shall  terminate  (as  shown  in 
the  figure)  in  a  tangent  F  G, 
parallel  to  and  at  a  given 
distance  H  G  from  D  H.  To 
determine  the  point  E  (the 
new  P.  C.  C. )  the  angle  ELF 
must  be  determined,  and  sub- 
stituted for  the  known  angle 
B  K  D.  From  C,  the  center 
of  the  larger  curve,  let  fall 
upon  F  G  the  perpendicular 
C G.  From  K and  L  let  fall  upon  C  G  the  perpendiculars  K M 
and  L  N.  Call  the  longer  radius  C  B,R\  the  shorter  radius 
K  D,  r;  the  distance  I  F  or  its  equal  H  G,  D;  the  angle 
B  K  D  ox  its  equal  K  C  M,x,  and  the  required  angle  ELF 
or  its  equal  L  C  N,  y.     Then, 


MN 


Fig.  362. 


{R  —  r)  COS  x-\-  D 
cos  y  =  ^ ^_^    ^     • 


(99.) 


That  is,  //le  distance  I  F  or  H  G  measured  rectangularly 
between  the  two  tangents,  being  added  to  the  difference  of  the 
radii  times  cos  x,  and  the  result  divided  by  the  difference  of 
the  radii,  tvill  give  the  cosine  of  the  angle  ELF,  or  y,  to  be 
turned  on  the  smaller  curve. 

Subtracting  the  angle j'  from  the  angle.!',  will  give  the 
angle  B  C  E,  to  be  added  to  the  larger  curve;  and  dividing 
this  angle  by  the  degree  of  curvature  in  ^  .5  we  find  the 
distance  from  B  to  E,  the  required  P.  C.  C. 

\i  E  F  h^  the  second  curve  located,  and  the  required 
tangent  lies  within,  i.  e.,  D  H  '\s  the  required  tangent,  it  is 
evident  that  instead  of  advancing  on  the  curve  A  B,  we  must 
retreat  on  it  to  find  the  required  P.  C.  C.  Accordingly, 
we  subtract  D  instead  of  adding,  as  in  the  preceding  case. 

Example. — A  B,  Fig.  362,  is  a  4°  curve  to  the  right,  located  and 
compounding  at  B  into  a  7'"  curve,  the  latter  being  continued  through 
an  angle  of  38°.     At  the  P.  T.  we  find  that  the  proper  tangent  is  46  ft. 


RAILROAD   LOCATION.  835 

to  the  left,  i.e.,  without  the  actual  tangent,  so  that  the  curve  will  be 
thrown  out  to  meet  the  required  tangent.  How  far  must  the  4°  ciirve 
be  continued? 

Solution. — The  radius  of  a  4°  curve  is  1,432.69  ft. ;  the  radius  of  a 
7=  curve  is  819.02  ft.,  hence,  R  -  r=  613.67  ft.  The  cosine  of  38°  = 
.78801.     Substituting  known  quantities  in  formula  99, 

(/?  -  r)  cos  X  4-  Z?      613. 67  X  .  78801  +  46       ^  _„.  . 

^^^■^  = -R^r = 613:67 =  '^^^^^ 

Hence,  angle  y  —  30°  21'.  Subtracting  this  angle  from  38"  00',  there 
remains  a  difference  of  7°  39',  which  must  be  added  to  the  4°  curve. 
7°  39'  reduced  to  decimal  form  is  7.65' -e- 4  gives  1.9125  stations  = 
191.25  feet,  which  must  be  added  to  the  4"  curve  to  reach  the  correct 
P.  C.  C.     Ans. 

In  the  above  example,  it  is  evident  that,  had  the  required 
tangent  been  within  the  given  tangent,  it  would  have  been 
necessary  to  move  the  P.  C.  C.  backwards  instead  of  advan- 
cing it.  This  will  increase  the  angle  y  of  the  second  curve, 
and,  consequently,  its  cosine  will  be  reduced.  The  distance 
D  will,  therefore,  be  subtracted  and  the  formula  will  read^ 

{R  —  r)  cos  X  —  D 
Q,o^yr=- '^ — .  (lOO.) 

K  —  r 

1424.  Problem  II. — Case  II.  When  the  second  curve 
is  of  longer  radius  than  the  first  curve: 

Let  A  B  F,in  Fig.  363,  be  a  compound  curve  terminating 
in  the  tangent  FH,  and  it  is  required  to  change  the  P.  C.  C. 
from  B  to  some  point  £  so  that  the  curve  shall  terminate  in 
the  tangent  D  G  parallel  to  F  H  and  at  a  given  distance 
H  G  from  it. 

Let  the  required  tangent  D  G  ho.  without  the  given 
tangent  F  H.  Calling  the  perpendicular  distance  H  G 
between  the  tangents  D\  the  radius  of  the  larger  curve,  /?, 
and  the  radius  of  the  smaller  curve,  r;  the  given  angle 
B  O  F  oi  the  second  curve,  ,r,  and  the  required  angle  E  C  G 
of  the  second  curve  j,  we  have,  as  in  formula  lOO, 

_  (/?  —  r)  cos  X  —  D 


cos  J 


R-r 


That  is,  the  distance  // 6^,  measured  rectangularly  between 
the  two  tangents,  should  be  subtracted  as  in  formula  lOO. 


836 


RAILROAD   LOCATION. 


It  will  be  seen  that  the  required  tangent  is  without  the 
given  tangent,  consequently,  it  will  be  necessary  to   move 

E 


Fig.  363. 

the  P.  C.  C.  backwards  on  the  first  curve,  i.  e.,  the  angle  of 
the  first  curve  must  be  reduced. 

Example. — A  ^  is  a  6°  curve  compounding  at  B  into  a  3'  curve 
whose  angle  is  42°  30',  and  whose  tangent  F  H  is  52  ft.  within  the 
required  tangent.     How  far  backwards  must  the  P.  C.  C.  be  moved  ? 

Solution. — The  radius  of  a  6°  curve  is  955.37  ft.,  and  the  radius  of 

a  3°   curve  is  1,910.08   ft.;   hence,    /?- r  =  1,910.08  -  955.37  =  954.71. 

Cos  x=  cos  42°  30'  =  .73728.    Substituting  the  known  values  in  formula 

^„„  ,  954.71  X.  73728 -52        ._„.        .  _    , 

lOO,  we  have  cos  y  ~ -.,  „^ =  .68281 ;  whence,  we  find 

•^  9o4.71 

y  =  46°  56'.     Deducting  42°  30'  from  46°  56',  we  have  a  diflference  of 

4°  26',  which  must  be  deducted  from  the  first  curve.     4°  26'  in  decimal 

form  is  4.433;  4.433  -¥■  6,  the  degree  of  the  first  curve,  gives  a  quotient 

of  .739  of  a  full  station  =  73.9  ft.,  the  distance  backwards  from  B  to  the 

correct  P.  C.  C.  at  E.     Ans. 

If  the  required  tangent  were  within  the  given  tangent, 
the  P.  C.  C.  would  be  advanced  and  the  angle  y  would  be 


RAILROAD   LOCATION. 


837 


reduced.     The   distance  D  would   then  be  added  and  the 
formula  would  read 


cos  J 


1425.  Problem  III. — To  avoid  obstacles  on  a  curve : 
Let  it  be  required  to  run  a  curve  A  DEC  between  the 
points  A  and  C,  and  suppose  an  obstacle  lies  directly  in  the 
path  of  the  curve.  The  obstacle  may  be  avoided  by  tracing 
a  parallel  curve  FG  HI,  and  from  the  stations  on  this  par- 
allel  curve,    the   corresponding  stations  on    the    required 


Fig.  3&4. 

curve    may   be   located.     The    process    is   as   follows  (see 
Fig.  364): 

Having  determined  either  P.  C.  or  P.  T.,  erect  a  per- 
pendicular A  F  to  the  tangent  A  K.  Now,  io  the  curve 
FGH I  it  is  evident  that  while  the  angle  AO  C  remains 
constant,  the  chords  F  G,  G  H,  and  HI  shorten  as  we 
approach  the  center  0  of  the  required  curve.     L,etAF  = 


838  RAILROAD    LOCATION. 

90  ft.,  and  the  radius  A  (9  =  819  ft.  The  chords  of  the 
required  curve  being  100  ft.  in  length,  we  have  the  follow- 
ing proportion :  O  A  :  O  A  —  A  F::100  :  F G,  Xhe^  length  of 
the  chord  of  the  parallel  curve. 

Substituting  known  values  in  the  proportion,  we  have 
819  :  729::  100  :  FG;  whence, /^  6' =  89.01ft.  Set  up  the  in- 
strument at  Fand  trace  the  curve  F  G  H  I,  setting  a  transit 
point  at  each  station  of  89.01  ft.  Then  set  the  transit  at 
each  of  these  points,  as  at  6",  and  turn  to  a  tangent  of  the 
curve  as  run.  Then,  turning  a  right  angle,  set  a  stake  90 
ft.  from  G,  locating  the  point  D.  In  a  similar  manner 
locate  each  of  the  stations  upon  the  required  curve. 

1426.  Problem  IV. — Having  given  two  angles  of 
intersection Z? -5  E  and  G F H,  and  the  distance  ^/'between 
the  points  of  intersection  (Fig.  365),  it  is  required  to  find 
the   radius   of   the  easiest  reverse  curve  which  will   unite 


Fig.  365. 

the  tangents  A  D  and  FK.  The  angle  D  B  E  \s  equal  to 
the  angle  A  O  E,  half  of  which  is  B  O  E.  The  angle  G  FN 
is  equal  to  the  angle  J5"  CG,  half  of  which  is  EC F.  Then, 
(tan  B  O  E -\- X.z.n  E  C  F)  \\.2.n  BO  E\\  BE  :  BE.  But 
E F  —  BE—  BE.     Reducing  the  proportion,  we  have 

_        tan  BO  Ex  BE 
tan  B  O E -\- tan  ECF' 

Now,  BE  is  the  tangent  distance  7^  of  the  curve  A  E,  and 


RAILROAD   LOCATION.  839 

substituting  known  values  in  formula  91,  T=R  tan  |/ 
(Art.  1251),  v^e  have  B  £=  O  £  tsin  B  O  £;  whence, 

B£  EF 

radius  O  E  =z and  radius  C E  = 


tan  B  O  E'  ^<^^^^^  ^  ^  -  ^^^  ^f-p- 

Example.— Let  the  angle  D  B  E,  Fig.  365,  =  40°  00',  the  angle 
G  F  H=m°  W,  and  the  distance  i?  7^=  922  ft.  Find  the  radius  of 
the  reverse  curve. 

Solution.— The  angle  BOE=\DBE  =  20°,  and  the  angle  ECF= 

iGFH=  31°  15'.     Tan  20°  =  .36397;  tan  31°  15'  =  .60681.     The  sum  of 

these  tangents  is  .97078,  and  we  have  the  proportion  .97078  :  .36397:: 

922  :  B  E\  whence,  we  find  ^  £"=  345.68  ft.     Substituting  the  value 

oi  BE  in  the  formula,  T  =  B  tan  i  /,  we  have  345.68  =  OEx  -36397 ; 

345  68 
whence,  we  have  radius  0E=    ,^"^-,  =949.75  ft.     Substituting  this 

. ooo9 I 

50 
value  of  ^  in  the  formula,  B  =  -. — =  (Art.   1249),  we  have  sin  D  = 

sin  D  ' 

50 
x-T7r-=rr,  whcncc,  sin  D  =  .05264  and  Z>  =  3°  01',  which,  multiplied  by  2, 
949. 75 

gives  6°  02',  the  required  degree  of  the  curve  A  E.     To  show  the 

student  that  the  curve  EG  is  of  the  same  degree  as  the  curve  A  E, 

we  complete  the  calculation  as  follows  :  B  F=  922  ft.  and  E F  =  922  — 

345.6»  =  576.32  ft.     Substituting  the  value  oi  EF'in  the  formula  T  = 

576  S'> 
R  tan  \  I,  we  have  radius  CE=  Z'JZ  =  949.75  ft.     Ans. 
"  .60681 

50 
Substituting  this  value  of  R  in  the  formula,  R  =  —. — ^,  we  have 

50 
sin D  =  „,_  ...  ,  whence  sin  D  =  .05264,  and  Z>  =  3°  01' ;  this,  multiplied 
949. 7o  >  r 

by  2,  gives  6°  02',  the  required  degree  of  the  curve  EG,  which  is  the 

same  as  that  of  the  curve  A  E.     Ans. 

1427.  Problem  V. — To  find  the  radius  of  a  curve 
which  will  be  tangent  to  three  given  straight  lines:  Let 
A  B,  B  C,  and  C  D,  in  Fig.  366,  be  the  given  lines,  then  the 
required  radius  will  be  equal  to 

BC^ 

tan  \  E  B  C  +  tan  \  E  C  B' 

Example.— Let  ^C  =  428  feet,  the  angle  ^^^  C=  23"  20,  and  the 
angle  EC B  =  'i>^°  20'.  Find  the  radius  of  the  curve  that  will  be  tan- 
gent Xo  A  B,  B  C,  and  CD. 

Solution.— Tan  i  EBC=. 20648,  and  tan  i  i5"Cy?  =  .22475.  The 
sum  of   these  tangents  is  .43123.     Substituting  these  values  in    the 


840  RAILROAD    LOCATION. 

equation,  radius  = —  „  _  ^^ .    ^^  „,  we  have  radius  = 


tan  i  £B  C  +  tan  ^  ECB'  .43123' 

whence  the  required  radius  =  992.51  ft.     Substituting  this  value  of  Ji 

50 
in  formula  89,  Art.   1249,  we  have  sin   Z>  =  p^-^  =  .05038,  and 

Z>  =  2°  53.3',  which,  multiplied  by  2,  gives  5°  46.6',  the  required  degree 


of  the  curve.  Ans.  The  required  degree  of  curve  may  be  found  by 
the  following  and  simpler  operation,  viz.:  Dividing  5,730  ft.,  the 
approximate  radius  of  a  1°  curve,  by  the  given  radius,  992.51  ft.,  we 
obtain  a  quotient  of  5.773°  =  5°  46.38',  a  result  amply  close  for  practical 
work.  The  angle  of  intersection  C£Fis  equal  to  EBC+ECB  = 
48°  40'.  Having  found  the  radius  and  angle  of  intersection,  the  tan- 
gent distance  is  calculated  by  formula  91,  T=  R  tan  |  /.  (See  Art. 
1251.) 

1428.  Problem  VI. — To  swing  a  tangent  so  that  it 
will  pass  through  a  given  point: 

Let  A  B^  in  Fig.  367,  be  a  curve  whose  tangent  .5  ^  passes 
through  the  point  C,  and  it  is  required  to  swing  the  tangent 
B  X  into  the  position  B'  X\  so  that  it  shall  pass  through 
the  point  C .  With  the  instrument  at  B  measure  the  angle 
C  B  C.  Divide  this  angle  by  the  degree  of  the  curve  A  B. 
The  quotient  will  be  the  distance,  in  stations,  which  must  be 
added  to  the  curve  A  B  to  bring  the  P.  T.  at  B\  and  the 
tangent  will  pass  through  the  required  point  C. 

Example. — Let  A  B  he  a.  6°  curve,  and  the  angle  C  B  C  =  4"  30'. 

Swing  the  tangent  .5  C  so  as  to  pass  through  the  point  C 

Solution. — Reducing  4°  30'  to  decimal  form  and  dividing  by  6,  the 

4  5 
degree  of  the  curve  A  B,  we  have-^  =  .75  of  a  full  station  =  75  ft., 

which  we  must  add  to  the  curve  A  B,  bringing  the  P.  T.  at  B',  and  the 
tangent  B'  X'  will  pass  through  the  point  C.     Ans. 

It  will  be  evident  that,  had  B'  X'  been  the  given  tangent 
and  C  the  required  point,  it  would  have  been  necessary  to 


RAILROAD   LOCATION. 


841 


move  the  point  of   tangent  B'  backwards  to  B,  i.   e.,   to 
subtract  75  ft.  from  the  given  curve. 


3130 


1 429.     Problem  VII. — To  find  the  distance  across  a 
river  in  a  preliminary  survey: 

Let  the  line  A  B,  Fig.  368, 
cross  a  river,  too  wide  for 
direct  measurement.  With 
the  instrument  at  A^  sight 
to  a  flag  held  at  B,  and  turn 
a.n  2ing\e  B  A  C  =  \° .  Seta 
plug  at  C,  opposite  B  in  the 
line  A  C,  and  measure  the 
distance  B  C. 

The  required  distance 
^  C"  X  100 


^^=       1.745 
Example  1.— If  BC- 


Fig.  368. 
10.6  ft.,  how  long  is  A  B7 


Solution.— y? B  =  ^^f^)^^  =  607. 45  ft.    Ans. 
1.745 


842 


RAILROAD    LOCATION. 


Example  2.— If  /)'t"  =  8.8  ft.,  how  long  is  A  B? 
8.8  X  100 


Solution. — A  B  ■ 


1.745 


=  504.3  ft.     Ans. 


1430.  Engineers'  Field  Books. — The  problems 
given  cover  the  cases  which  are  liable  to  arise  under  ordi- 
nary conditions,  and  the  explanations  have  been  fully  given. 
The  engineer  must  necessarily  carry  a  field  book  containing 
the  usual  tables  of  reference.  All  standard  field  books  con- 
tain demonstrations  of  problems  covering  all  those  special 
cases  which  do  not  properly  come  within  the  scope  of  this 
work. 

1431.  Relative  Position  of  Preliminary  and 
Located  Line. — The  relative  position  of  the  preliminary 
and  of  the  located  line, 
where  the  work  has 
been  intelligently  per- 
formed, is  shown  in  the 
following  sketch,  Fig. 
369,  in  which  the  pre- 
liminary line  is  shown  V'  The  location  is 
in  dotted  and  the  loca-  ^^  practically  fixed 
tion  in  full  lines.                 fV  X       \  \     by  the  preliminary 

line,    leaving    little 
to  do  but  to  run  in 
the   curves.       The 
slight  changes  in  the 
direction  of  the  tan- 
gents  and  the  degrees  of  the  curves 
will  be  determined  by  an  inspection  of 
the  contour  map,  which  is  the  basis  of 
every  intelligent  location. 

1432.  Field  Profiles.— The  profile  is  kept  plat- 
ted as  fast  as  the  line  is  located,  in  order  that  the  chief 
of  party  may  know  how  nearly  the  actual  profile  ap- 
proximates to  the  theoretical  one  (the  one  that  is  made 
from  the  paper  location)  and  what  changes  may  be 
necessary. 


Fig.  3C9. 


RAILROAD   LOCATION. 


843 


1433.  Final  Location. — After  the  right  of  way  has 
been  cleared,  affording  an  unobstructed  view  of  the  ground, 
it  will  frequently  be  seen  that  slight  changes  in  the  located 
line  will  greatly  reduce  the  cost  of  construction ;  and  not 
until  such  changes  are  made  will  the  engineer  have  made 
the  fitial  location. 

None  but  experienced  engineers  can  understand  how  a 


Area^4.5  Sq.ft. 

Fill  30ft 

T 


Fig.  370. 

slight  change  in  location,  especially  on  a  side  hill  line,  can 
so  greatly  affect  cost;  and  it  is  first  cost  which  generally  de- 
termines the  success  or  failure  of  the  enterprise. 

The  accompanying  sketches  will  afford  some  light  where  it 
is  oftenest  needed.  Fig.  370  is  an  example  of  poor  location 
more  often  met  with  than  that  of  any  other  kind,  and  yet 
one  where  a  little  conscientious  work,  together  with  common 


nil  5.8ft 


Fig.  371. 

sense,  would  have  produced  amazing  results,  as  shown  in  Fig. 
371,  which  is  decidedly  good  location.  Side  hills  afford  op- 
portunity for  almost  the  cheapest  form  of  construction.     A 


844  RAILROAD    LOCATION. 

grade  line,  i.  e. ,  where  the  grade  coincides  with  the  surface 
of  the  ground  on  the  center  line,  as  in  Fig.  371,  can,  unless 
rock  is  encountered,  be  graded  with  pick  and  shovel  alone, 
the  men  casting  the  material  taken  from  the  cut  directly 
into  and  making  the  fill.  The  area  of  the  cut  in  Fig.  370  is 
49.8  sq.  ft.,  while  the  area  of  the  fill  is  but  4.5  sq.  ft.,  leaving 
an  excess  of  excavation  of  45.3  sq.  ft.,  or  ten  times  the  area 
of  the  fill.  There  is  no  way  by  which  this  excess  of  mate- 
rial can  be  utilized ;  it  must,  therefore,  be  wasted,  as  has 
been  the  labor  of  excavating  it.  By  moving  the  center  line 
4  feet  to  the  right,  we  obtain  the  cross-section  shown  in  Fig. 
371,  in  which  the  calculated  areas  of  cut  and  fill  are  as  fol- 
lows: Cut,  19.2  sq.  ft. ;  fill,  20.3  sq.  ft. ;  a  difference  of  less 
than  1  sq.  ft.,  and  the  excess  is  on  the  right  side,  for  a  ditch 
should  be  made  four  feet  from  the  top  of  the  upper  slope  to 
prevent  the  washing  down  of  the  slope,  and  this  material 
will  more  than  equal  the  excess  of  the  fill  over  the  cut. 

1434.  Referencing  Transit  Points.  — Having  com- 
pleted the  final  location,  the  points  of  curve  and  points  of 
tangent  must  be  referenced,  and  also  intermediate  points 
where  a  change  of  grade  requires  it.  Such  an  intermediate 
point  is  shown  in  Fig.  372. 


Fig  372. 


The  line  ABC  from  the  P.  T.  at  A  to  the  P.  C.  at  C  is 
straight,  but  the  transit  pole  at  C  can  not  be  seen  through 
the  transit  SitA  on  account  of  the  change  of  grade  at  B.  It 
is,  therefore,  necessary  to  establish  an  intermediate  point  at 
B  on  the  line  ABC.  The  transit  being  set  up  at  B,  both 
P.  T.  and  P.  C.  are  in  full  view. 

A  good  example  of  referencing  is  shown  in  Fig.  373.  The 
reference  points  consist  of  plugs  driven  flush  with  the 
ground  and  protected  by  substantial  guard  stakes,  which  are 


RAILROAD   LOCATION. 


845 


marked  with  the  letters  JR.  P.  Where  the  located  line  trav- 
erses timber  or  brushwood,  the  ordinary  stakes  on  the 
center  line  should  be  replaced  by  much  larger  ones.  They 
are  best  cut  from  saplings  about  3  feet  in  length  and  from 
2^  to  3^  inches  in  diameter.  A  place  for  the  stake  is  made 
with  an  iron  bar,  and  the  stake  driven  at  least  one  foot  in 
the  ground  with  a  sledge  hammer.     Special  care  is  taken  in 


*lug  and 
Guard  Stake 


Plug  and 
Guard  Stake 


£C 


Fig.  373. 


guarding  points  of  curve  and  tangent.  While  the  right  of 
way  is  being  cleared  a  man  is  detailed  to  look  after  the 
stakes  and  hubs  on  the  center  line,  as  many  will  be  disturbed 
or  torn  out  of  the  ground  while  hauling  logs  and  timber 
from  the  right  of  way.  When  the  clearing  and  burning  is 
completed,  the  center  line  should  be  rerun,  restoring  all 
lost  or  disturbed  stakes.  Transit  points,  if  well  set,  will 
rarely  be  disturbed.  When  the  center  line  is  restored  the 
transit  points  are  referenced.  A  little  care  and  judgment 
will  enable  the  engineer  to  select  reference  points  which  will 
remain  undisturbed  during  the  work  of  construction. 
Where  the  work  is  heavy  these  points  will  be  further  re- 
moved from  the  center  line  than  at  points  where  the  work 
is  light. 

When  the  grading  is  completed,  the  original  points  of 
curve  and  tangent  can  be  restored  and  the  center  line  run 
in  from  both  ends  of  the  curve.  Any  small  error  in  aline- 
ment  due  to  inaccuracies  in  the  measurement  of  the  original 
line  will  then  be  thrown  on  the  middle  of  the  curve,  where 


846  RAILROAD    LOCATION. 

they  will  not  in  any  way  affect  the  excellence  of  the  work, 
and  the  tangents  will  remain  unchanged. 

1435.  Final  Levels. —While  the  transit  points  are 
being  referenced,  the  leveler  takes  the  final  levels^  reading 
all  turning  points  with  the  target  and  correcting  all  bencli 
marks.  He  need  not  hurry,  as  accuracy  is  all  important. 
An  error  in  final  levels  is  unpardonable,  as  the  work  of  con- 
struction is  based  upon  them.  Most  errors  in  field  work  are 
directly  chargeable  to  carelessness.  A  bench  mark  is  estab- 
lished at  each  bridge  site,  and  at  all  points  of  the  line  where 
permanent  structures,  such  as  arch  culverts,  trestles,  water 
tanks,  stations,  etc.,  are  to  be  built.  The  final  profile  is 
platted  from  these  levels  and  the  grade  line  drawn  in  pencil. 
The  points  of  curve  and  tangent  are  marked  in  small  cir- 
cles on  one  of  the  horizontal  lines  at  the  bottom  of  the  pro- 
file. That  portion  of  the  line  corresponding  to  tangents  is 
drawn  in  a  full  line,  and  the  balance,  representing  the 
curves,  in  broken  line.  The  stations  of  the  points  of  curve 
and  tangent  are  also  numbered  on  the  profile. 

The  compensations  for  curvature  are  then  calculated,  and 
the  final  grade  line  drawn  in  ink. 

1436.  Compensation    for    Curvature.  — From   .03 

to  .05  ft.  per  degree  is  the  compensation  or  reduction  in 
grade,  made  for  the  added  resistance  due  to  curvature,  i.  e. , 
where  the  established  grade  for  tangents  is  1  per  cent.,  the 
grade  on  a  6°  curve,  allowing  a  compensation  of  .03  ft.  per 
degree,  would  be  LOO— (.03  ft.  x  6)  — .82  per  cent.  Where 
a  compensation  of  .05  ft.  per  degree  is  made,  the  grade  on 
a  G°  curve  would  be  1.00  — (.05  X  n)  =  .70  per  cent. 

1437.  Final  Grade  Lines. — The  establishing  oi  final 
grade  lines  is  illustrated  in  Fig.  374,  where  the  uncompen- 
sated grade  is  1.3  per  cent.,  and  the  compensation  for 
curvature  as  shown  in  the  final  grade  line  is  .03  ft.  per 
degree. 

The  location  notes  for  the  line  included  in  the  diagram  are 

as  follows: 

I* 


RAILROAD   LOCATION. 


847 


Stations. 

Intersection  Angles. 

52  +  00 

End  of  Grade. 

49  +  75  P.  T. 

44  +  25  P.  C.  9°  R. 

49°  30' 

~      42  +  00  P.  T. 

37  +  50  P.  C.  6°  L. 

27°  00' 

33  +  00  P.  T. 

29  +  00  P.  C.  8°  R. 

32°  00' 

27  +  00 

Beginning  of  Grade. 

The  profile  is  made  to  standard  scales,  viz.,  horizontal 
400  ft.  =  1  in. ;  vertical,  20  ft.  =  1  in.  The  elevation  of  the 
grade  at  Sta.  27  is  fixed  at  120  ft.,  and  at  Sta.  52  at  152.5  ft., 
giving  between  these  stations  an  actual  rise  of  32.5  ft.  and 
an  uncompensated  grade  of  1.3  per  cent.  These  grade  points 
we  mark  on  the  profile  in  small  circles.  The  total  curvature 
between  Sta.  27  and  Sta.  52  is  108^°.  The  resistance  due  to 
each  degree  of  curvature  being  taken  as  equivalent  to  an  in- 
crease of  .03  ft.  in  grade,  the  total  resistance  due  to  108. 5°  is 
equal  to  .03  ft.  X  108.5  =  3.255  ft.,  and  is  equivalent  to 
adding  3.255  ft.  to  the  actual  rise  between  Sta.  27  and  Sta.  52. 
Hence,  the  total  theoretical  grade  between  these  stations  is 
the  sum  of  32.5  ft.,  the  actual  rise,  and  3.255  ft.  due  to 
curvature,  which  is  35.755  ft.     Dividing  35.755  by  25,  the 

35  755 
number  of  stations  in  the  given  distance,  we  have^ — ^-- —  = 

25 

+  1.4302  ft.,  the  grade  for  tangents  on  this  line.    The  starting 

point  of  this  grade  is  at  Sta.  27.  The  P.  C.  of  the  first  curve 

is  at  Sta.  29,  giving  a  tangent  of  200  ft.  =  2  stations.     As 

the  grade  for  tangents  is  +  1.4302  ft.  per  station,  the  rise  in 

grade   between   Stas.   27  and  29  is  1.4302X2  =  2.8604  ft. 

The  elevation  of  the  grade  at  Sta.   27  is  120  ft.,  and  the 

elevation  of  grade  at  Sta.  29  is  120  +  2.8604  =  122.8604  ft., 

which  we  record  on  the  profile  as  shown  in  Fig.  374,  with  the 


848  RAILROAD   LOCATION. 

rate  of  grade,  viz.,  -j-  1.4302  written  above  the  grade  line. 
The  first  curve  is  8°,  and  as  the  compensation  per  degree  is 
.03  ft.  for  8°,  or  a  full  station,  the  compensation  is  .03  ft.  X 
8  =  .24  ft.  The  grade  on  the  curve  will,  therefore,  be  the 
tangent  grade  minus  the  compensation,  or  1.4302  —  .24  ft.  = 
+  1.1902  ft.  per  station.  The  P.  C.  of  this  curve  is  at 
Sta.  29,  the  P.  T.  at  Sta.  33,  making  the  total  length  of  the 
curve  400  ft.  =  4  stations.  The  grade  on  this  curve  is  -|- 
1.1902  ft.  per  station,  and  the  total  rise  on  the  curve  is 
1.1902  X  4  =  4.7608  ft.  The  elevation  of  the  grade  at  the 
P.  C.  at  Sta.  29  is  122.8604;  hence,  the  elevation  of  grade  at 
the  P.  T.  at  Sta.  33  is  122.8604  +  4.7608  =  127.6212  ft., 
which  we  record  on  the  profile  together  with  the  grade,  viz., 
+  1.1902,  written  above  the  grade  line.  The  P.  C.  of  the 
next  curve  is  at  Sta.  37  +  50,  giving  an  intermediate 
tangent  of  450  ft.  =  4.5  stations.  The  grade  for  tangents 
is  +  1.4302  ft.  per  station;  hence,  the  total  rise  on  the 
tangent  is  1.4302  X  4.5  =  6.4359  ft.  Adding  6.4359  ft. 
to  127.6212  ft.,  we  have  for  the  elevation  of  grade  at  Sta. 
37  +  50,  134.0571  ft.,  which  we  record  on  the  profile,  to- 
gether with  the  rate  of  grade  for  tangents. 

The  next  curve  is  6°  and  the  compensation  in  grade  per 
station  is  .03  ft.  X  6  =  .18  ft.  The  grade  on  this  curve  will, 
therefore,  be  1.4302  —  .18  =  1.2502  ft.  per  station.  The 
length  of  the  curve  is  450  ft.  =  4.5  stations,  and  the  total 
rise  in  grade  on  this  curve  is  +  1.2502  ft.  x  4.5  =  5.6259  ft. 
The  elevation  of  the  grade  at  Sta.  37  +  50,  the  P.  C. 
of  the  curve,  is  134.0571.  The  elevation  of  the  grade  at 
Sta.  42,  the  P.  T.,  is,  therefore,  134.0571  +  5.6259  =  139.683 
ft.,  which  we  record  on  the  profile  together  with  the  rate  of 
grade  on  the  6°  curve,  viz. ,  +  1. 2502.  The  P.  C.  of  the  next 
curve  is  at  Sta.  44  +  25,  giving  an  intermediate  tangent  of 
225  ft.  =  2.25  stations.  The  total  rise  on  the  tangent  is, 
therefore,  1.4302  X  2.25  =  3.21795  ft.  The  elevation  of  grade 
at  the  P.  T.  at  Sta.  42  =  139.683;  therefore,  the  elevation  of 
grade  at  Sta.  44  +  25  =  139.683  +  3.21795  ft.  =  142.90095  ft., 
which  we  record  on  the  profile  together  with  the  grade,  viz., 
+  1.4302.     The  last  curve  is  9°  and  the  compensation  in 


RAILROAD   LOCATION. 


849 


30 


grade  per  station  is 
.03  ft.  X  9  =  .27  ft. 
The  grade  on  9°  curve 
is,  therefore,  1.4302  — 
.27  =  1.1602  ft.  per  sta- 
tion. The  length  of 
the  curve  is  550  ft.  = 
5.5  stations,  and  the 
total  rise  on  the  curve 
is  1.1602X5.5  =  6.3811 
ft.  The  elevation  of 
grade  at  Sta.  44  +  25, 
the  P.  C.  of  the  9° 
curve,  is  142.90095  ; 
hence,  the  elevation  of 
grade  at  the  P.  T., 
at  Sta.  49  +  75,  is 
142.90095  +  6.3811  = 
149.28205  ft.,  which  we 
record  on  the  profile  to-  ?  ^q 
gether  with  the  grade,  % 
+  1.1602.  The  end  of 
the  line  is  at  Sta.  53, 
giving  a  tangent  of 
225  ft.  =  2.25  stations. 
The  rise  on  this  tan- 
gent is  1.4302x2  25  = 
3.21795  ft.,  which  we 
add  to  149.28205,  the 
elevation  of  the  P.  T.  at 
Sta.  49+75.  The  sum, 
152.5  ft.,  is  the  eleva- 
tion of  grade  at  Sta. 
52.  The  sum  of  the 
partial  grades  should 
equal  the  total  rise  be- 
tween the  extremities 
of    the    grade    line. 


60 


850 


RAILROAD   LOCATION. 


The  points  where  the  changes  of  grade  occur  are  marked  on 
the  profile  in  small  circles,  which  are  connected  by  fine  lines 
which  represent  the  grade  line.  These  points  of  change  are 
projected  on  a  horizontal  line  at  the  bottom  of  the  profile. 
Those  portions  of  this  line  representing  curves  are  dotted, 
and  those  portions  representing  tangents  are  drawn  full. 
The  points  of  curve  P.  C.  and  P.  T.  are  marked  in  small 
circles  on  this  horizontal  line,  and  lettered  as  shown  in  the 
figure. 

Where  the  grades  are  light  and  the  curves  easy,  there  will 
be  no  need  of  compensation  for  curvature.  Where  the  grades 
exceed  .5  per  cent,  and  the  curves  5°,  compensation  should 
be  made. 

1 438.  Changing  of  Grade  Lines. — Unforeseen  diffi- 
culties sometimes  arise  during  construction  which  warrant 
the  changing  of  grade  lines,  but  these  occasions  are  rare. 
If  the  final  grade  line  has  been  properly  considered,  it  would 
better  remain  unchanged.  The  engineer  should  learn  to 
make  up  his  mind  and  stick  to  it. 

1 439.  Vertical  Curves. — Vertical  curves  are  used  to 
round  off  the  angles  formed  by  the  meeting  of  two  grade 


lines.     Let  A   C  and  C  B,   Fig.    375,  be  two   grade  lines 
meeting  at  C. 

These  grades  are  given  by  the  rise  per  station  in  going  in 
some  particular  direction.  Thus,  starting  from  A,  the 
grades  A  C  and  C  B  may  be  denoted  by  g  and  g' \  that 
is,  the  grade  for  any  station  on  y^  (7  is  found  by  adding  the 


RAILROAD   LOCATION.  851 

rate  of  grade  g  to  the  grade  of  the  preceding  station,  and 
the  grade  for  any  station  on  C  ^  is  found  by  adding  the  rate 
of  grade  g'  to  the  grade  of  the  preceding  station.  But  C  B 
is  a  descending  grade.  Therefore,  the  rate^',  to  be  added 
to  each  station,  is  a  minus  quantity  and^'  is  negative. 

The  parabola  furnishes  a  simple  method  of  putting  in  a 
vertical  curve. 

1440.  Problem.— Given  the  grade  ^  of  A  C,  Fig.  375, 
the  grade  ^'  of  C  B,  and  the  number  of  stations  n  on  each 
side  of  C  to  the  tangent  points  A  and  B,  to  unite  these 
points  by  a  parabolic  vertical  curve : 

Let  A  £  B  he  the  required  parabola.  Through  B  and  C 
draw  the  vertical  lines  F  K  and  C  H,  and  produce  A  C  to 
meet  F  K  in  F.  Through  A  draw  the  horizontal  line  A  K 
and  join  A  and  /?,  cutting  C  H  \n  D.  Then,  if  a  represents 
the  vertical  distance  of  the  first  station  M  on  the  curve 
from  the  corresponding  station  7"  on  the  tangent,  the  ver- 
tical distance  at  the  second  station  will  be  the  square  of 
2,  or  4  «,  and  at  the  third  station  the  square  of  3,  or  9  «, 
and  at  B,  which  is  2  «  stations  from  A,  the  vertical  distance 
to  the  curve  will  be  the  square  of  2  «  or  4  «" « ;  that  is,  F  B  =^ 

FB 
4  «'  a,  and  a  =  - — j.     To  find  a,  it  will  first  be  necessary 

to  find  F  B.  This  may  be  done  by  means  of  the  following 
formula,  in  which  g  and  g'  are  the  grades  mentioned  in 
Art.  1439,  and  n  is  the  number  of  stations  between  A 
and  C: 


4  n 


(lOl.) 


Having  determined  the  value  of  a,  the  distances  of  the 
several  stations  in  A  C  and  C  B  from  the  curve,  viz.,  a,  4  a, 
9  a,  16  n,  etc.,  are  readily  known.  Let  T  and  F'  be  the 
first  and  second  stations  on  the  tangent  A  C,  and  if  from  T 
and  T'  perpendicular  lines  T  P  and  T'  P'  be  drawn  to  the 
horizontal  line  A  K,  T  P,  the  height  of  the  first  station  T 
above  A,  equals^,  and  7  '  P'  equals  2^,  and  for  succeeding 
stations  we  shall  find  the  heights  3  g,  4  g,  etc.     We  have 


852  RAILROAD   LOCATION. 

already  found  T  M—a,  T'  M'  =  A:  a,  etc.  The  heights  of 
the  curve  above  the  level  of  A  will,  therefore,  be  as  follows: 
K\.M,  heights  TP-  T  M=g-  a;  at  J/',  height  =  T'  P' 

—  T'  M'  =  2g-Aa,  and  at  E,  height  =C  H  -  C  E^Zg 

—  9  rt,  and  for  succeeding  points  A  g  —  16  «,  etc.  To  find 
the  grades  for  the  curve  at  successive  stations  from  A,  that 
is,  the  amount  which  must  be  added  to  the  grade  or  height 
of  one  station'to  equal  the  grade  of  the  following  station,  we 
must  subtract  each  height  from  the  next  following  height. 
Thus,  calling  the  height  of  A  0,  we  have  (^  —  «)  —  0  =  ^ 

—  a^  the  height  of  M  above  A  K,  called  the  grade  of  M; 
(2^—4  a)  —{g  —  (i)  =  g  —  3  a,  which  must  be  added  to  the 
grade  of  J/ to  find  the  grade  of  J/' ;  (3^  —  9  «)  —  (2  ^  —  4  «) 
=  g—  5  a,  which  must  be  added  to  the  grade  of  Af  to  find 
the  grade  of  E.  The  succeeding  quantities  are  (4^  —  16  a) 
-{3g-9a)=g-'7  a,{5  g-  25  a)  -  (4^-16  a)  =  g - 
9  a,  and  {&  g —ZQ  a)  —  {5  g  —  2b  a)  =  g  —  \l  a.  The  suc- 
cessive grades  or  additions  for  the  vertical  curve.  Fig. 
375,  are  ^  -  ^,  g-Z  a,  g-  5  a,  g-7  a,  g-d  a,  and 
g-lla. 

In  finding  these  grades,  strict  regard  must  be  paid  to  the 
algebraic  signs.     The  results  are  then  general. 

1441.  Example  1. — Let  the  number  of  stations  on  each  side 
of  C,  Fig.  375,  be  3,  and  let  A  Che  an  ascending  grade  of  1.2  feet  per 
station,  and  C  B  a.  descending  grade  of  .8  ft.  per  station.  Assume  the 
elevation  of  the  grade  at  Sta.  A  to  be  120  feet,  and  find  the  grade  at 
each  station  from  A  to  B. 


Solution. — Here  «  =  3,  ,^  =  +  1.2  ft.,  and  ^'  =  —  .8  ft.      Substitu- 

-^'       1-              1.2-(- 
-i-2-,we  have  a  — .  ^  ^ 

—     1  AAA  ft-       onH    fVio  crfiir1*»c  frf\rr\     A    \r\ 

12 


p—  z'  1  2  —  (—  .8) 

ting  known  values  in  formula  1  Ol ,  a  =     ,       ,we  have  a  — 

4« 

2  0 

Yq  =  .1666  ft.,  and  the  grades  from  A  to  B  will  be 


Heights  of  Curve 
above  A. 
g-  a  =1.2-  .167=  1.033  ft.  1.033  ft. 
g-  Za  =  1.2  -  .500  =  .700  ft.  1.733  ft. 
^-5^=1.2-  .833=  .367  ft.  2.100  ft. 
^-  7a  =1.2-1.166=  .034  ft.  2.134  ft. 
^-  9a  =1.2-1.500=-  .300  ft.  1.834  ft. 
g  -  11a  =  1.2  -  1.833  =  -    .633  ft.  1.201  ft. 


RAILROAD   LOCATION. 


853 


Since  the  elevation  of  the  grade  at  Sta.  A,  Fig.  375,  is  120.00  feet,  the 
grades  for  the  following  stations  of  the  vertical  curve  will  be : 

Elevation  of       „^  ^.  Elevation  of 

tation.  „      .  Station.  „      . 

Grade.  Grade. 

A  120.000  ft.  O 122.134  ft. 

M 121.033  ft. 

M' 121.733  ft. 

E  122.100  ft. 


Ans. 


R 121.834  ft. 

B 121.201  ft. 


Example  2. — Let  A  C,  Fig.  376,  be  a  descending  grade  of  1.0  ft.  per 
station,  and  C  B  an  ascending  grade  of  .5  ft.  per  station.  Let  the 
vertical  curve  include  2  stations  each  side  of  C.  Find  the  grade  at 
each  station  from  A  \.o  C. 

Solution.— Here  g  =—  1.0  ft.,  ^'  =  +  .5  ft.,  and  «  =  2.    Substituting 


GTade=120.0 


Fig.  376. 


these  values  in  formula  lOl,  a=.'^^ — ^— ,  we  have 

4  « 

-1.5 


a^-\.0-{.h)  _ 


=  —  .IS'* 5,  and  the  four  grades  required  will  be: 


Ans. 


g-  a  = 
g-Za  = 
g  -oa  = 
g-'7a  = 


1.0 -(-  .1875)  = 
1.0 -(-  .5625)  = 
1.0 -(-  .9375)  = 
1.0 -(-1.3125)  = 


1.0+  .1875  = -.8125  ft. 
1.0  +  .5625  =  -  .4375  ft. 
1.0+  .9375  =- .0625  ft. 
1.0  +  1.3125=  +  .3125  ft. 


It  will  be  seen  that  after  finding  the  first  grade,  the  suc- 
ceeding grades  are  found  by  a  continual  subtraction  of  2  a. 
Thus,  in  the  first  example,  each  grade  after  the  first  is  .333  ft. 
less  than  the  preceding  grade.  In  the  second  example,  a  is 
a  negative  quantity,  and  each  grade  after  the  first  is. 375 ft. 
greater  than  the  preceding  grade. 

The  grades  in  the  foregoing  examples  are  calculated  for 
whole  stations,  and  are  sufficient  for  all  purposes  except  for 
track  laying  or  ballasting,  when- grade  stakes  on  the  vertical 
curve  should  be  driven  at  intervals  of  25  feet,  and  the  grades 
must  be  calculated  for  these  sub-stations.     To  do  this,  let  g" 


854  RAILROAD   LOCATION. 

and^'  represent  the  grades  for  a  sub-station  of  25  feet,  and 
11  the  number  of  such  sub-stations  on  each  side  of  the 
intersection  of  the  grade  lines. 

Example. — In  the  last  example  divide  the  curve  into  sub-stations  of 
25  ft.  each.  Assume  the  grade  at  A  to  be  130  feet,  and  find  the  grade 
at  each  sub-station. 


Solution.— Here  ^=—.25  ft,  ^'  =  +.125  ft.,  and  «  =  8.  Sub- 
stituting  these  values  in  formula  lOl,  <?  =  .  *  ,  we  have  a-= 
-.25 -(.125)  ^  -^  ^  _  ^^^^2       ^^^    ^^^^    g^^^^    .^^    therefore. 

^  -  rt  =  -  .25  -  (-  .01172)  =  -  .23828.  Each  subsequent  grade  in- 
creases 2a;  that  is,  —.02344,  and  we  have  the  following:  Grade  at 
Sta.  2  =  -  .21484;  Sta.  3,  -  .19140;  Sta.  4,  -  .16796;  Sta.  5,  -  .14452; 
Sta.  6,  -.12108;  Sta.  7,  -.09764;  Sta.  8,  -.07420;  Sta.  9,  -.05076; 
Sta.  10.  -  .02732;  Sta.  11,  -  .00388;  Sta.  12,  +  .01956;  Sta.  13,  +  .04300; 
Sta.  14,  +.06644;  Sta.  15,  +.08988;  Sta.  16,  +.11332. 

The  distance  A  />',  Fig.  376,  is  400  feet  divided  into  16  sub-stations  of 
25  feet  each.  Since  the  grade  of  A  is  120.0  feet,  the  grades  of  the  fol- 
lowing stations  will  be: 

f  Stations.    Grades.  Stations.      Grades. 

A 120.000  9 118.699 

1 119.762  10 118.672 

2 119.547  11 118.668 

3 119.355  12 118.688 

4 119.187  13 118.731 

5 119.043  14 118.797 

6 118.922  15 118.887 

7 118.824  16,  i5...  119. 000 

8 118.750 

The  purpose  served  by  vertical  curves  will  be  at  once  ap- 
parent to  the  student.  The  sudden  and  severe  stress  upon 
the  rolling  stock  caused  by  passing  from  one  grade  to 
another  results  in  great  harm  to  rolling  stock  and  much 
discomfort  to  passengers.  Vertical  curves  should  always  be 
put  in  the  grade  during  construction.  Where  the  meeting 
grades  are  very  slight,  no  curve  is  necessary. 

1 442.  Preliminary  Estimates. — Having  established 
the  final  grades,  the  next  work  of  the  engineer  is  the  pre- 
liminary estimate.  This  estimate  gives  in  detail  the  approx- 
imate quantities  of  all  material  to  be  handled  in  the  work  of 


Ans. 


kAILROAD   LOCATION.  856 

construction,  and  of  all  probable  cost  attending  such  work. 
Work  and  materials  to  be  furnished,  together  with  the  prices 
ruling  in  the  locality  where  the  work  is  to  be  done,  are 
classified  as  follows: 

1 443.    Classification  of  Preliminary  Estimates. — 

1.   Clearing  per  acre $20.00. 

^  Earth,  per  cubic  yard 20c. 

}  Loose  rock,  per  cubic  yard. .  40c. 

■ '  '  '   (  Solid  rock,  per  cubic  yard. .  .  80c. 

Overhaul  exceeding  1,000  feet,  per  cubic  yard  Ic. 

Piles,  per  lineal  foot 25c.  to  30c. 

3.  Trestling.  \  Frame,  per  1,000  ft.  bd.  meas- 
ure, Ga.  pine $35.00. 

Ist-class    rock-face    range 

work,  per  cubic  yard $10. 00  to  $12  00. 

'2d-class    good    lime    mortar 

rubble,  per  cubic  yard.  . .  .  $8.00. 

Dry  rubble,  per  cubic  yard. .  $4. 00  to  $4. 50. 
Riprap  per  square  yard,   in 

place $1.50to$2.50. 

Wooden 

[ron  and  steel 


4.  Masonry..  ■< 


5.   Bridgmg  .  -j  ^^ 


Classification  not  only  affects  price,  but  quantity.  Cuts 
in  solid  rock,  which  are  the  most  costly,  stand  at  a  slope  of 
^  horizontal  to  1  vertical,  while  earth  ordinarily  requires  a 
slope  of  1  horizontal  to  1  vertical,  and  sometimes  as  flat  a 
slope  as  1|^  horizontal  to  1  vertical.  All  materials  excavated, 
and  all  masonry,  are  estimated  by  the  cubic  yard.  Trest- 
ling is  estimated  by  the  1,000  feet,  board  measure,  and 
piling  by  the  lineal  foot.  Wooden  bridges,  of  moderate 
span,  are  sometimes  estimated  at  a  fixed  price  per  1,000  feet 
for  lumber,  and  a  fixed  price  per  lb.  for  iron,  but  generally 
a  special  estimate  is  made  for  each  bridge.  The  cost  of 
bridges  increases  rapidly  as  the  span  increases.  In  metal 
bridges  the  cost  will  increase  about  as  the  square  of  the 


856 


RAILROAD   LOCATION. 


span,  i.  e.,  if  one  bridge  has  twice  as  great  a  span  as  another, 
the  first  will  cost  the  square  of  2  or  4  times  as  much  as  the 
second. 

1444.*  Quantities. — The  material  to  be  handled  in 
grading  the  roadbed  is  generally  estimated  by  level  cuttings, 
which   process  assumes  that  the  cross-section  surfaces  are 


1/  9.0  ft 


t  4.4ft 


Fig.  377.     ' 

level,  and  the  areas  are  calculated  from  the  center  cuts  and 
Ji//s.  Let  Fig.  877  represent  the  actual  cross-section  at  a 
given  station,  and  Fig.  378  the  cross-section  based  upon  the 
center  cut.  The  area  of  the  section  A  B  C  D  m  Fig.  377, 
calculated  from  the  actual  cross-sections,  is  160.78  sq.  ft. 
The  area  of  the  section  A'  B'  C  D\  in  Fig.  378,  calculated 


Cut  6.4  ft 


Cut  6.4  ft 


JS.4- -i 


15.4.^- > 


1^ 6^ 1— 


Fig.  378. 


Cut  6.4ft 


V 6d . 


from  a  level  section,  with  the  same  center  cut,  viz.,  6.4  feet, 
is  156.16  sq.  ft.,  giving  a  discrepancy  of  4.62  sq.  ft. ;  that  is, 
the  area  of  the  section,  calculated  by  level  cuttings,  is  4.62 
sq.  ft.  less  than  the  area  calculated  from  the  actual  cross- 
sections.  This  deficiency  is  about  3  per  cent.,  but  where 
the  slope  is  very  steep,  the  difference  increases  rapidly.  As 
the  invariable  custom  is  to  add  10  per  cent,  to  the  estimated 


RAILROAD   LOCATION. 


857 


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858  RAILROAD   LOCATION. 

cost,  such  addition  will  fully  cover  any  deficiency  resulting 
from  table  calculations.  Where  time  is  not  an  object,  it  is 
good  practice  to  take  the  slopes  with  a  clinometer  and  plat 
them  on  cross-section  paper.  The  estimate  thus  obtained 
will  be  a  close  approximation  to  the  actual  quantities 
handled  in  the  work  of  construction.  For  work  in  the 
Northern  and  Middle  States  the  following  rates  of  slope  are 
standard:  For  embankments,  H  horizontal  to  1  vertical; 
for  earth  cuts,  1  horizontal  to  1  vertical,  and  for  rock  cuts, 
^  horizontal  to  1  vertical.  In  Western  and  Southern  States 
it  is  the  usual  custom  to  give  to  cuts  the  same  slope  as  to 
embankments,  viz.,  1^  horizontal  to  1  vertical. 

1445.  Traut^vine's  Engineers'  Pocket  Book  con- 
tains complete  tables  of  level  cuttings  for  standard  widths 
of  roadway,  both  single  and  double  track.  The  slopes  are 
given  for  earthwork,  both  excavation  and  embankment. 
The  quantities  are  calculated  for  sections  100  feet  apart.  If 
the  sections  are  taken  oftener  than  each  100  feet,  the  quan- 
tities will  be  proportionally  less.  The  table  of  Level  Cut- 
tings shows  the  arrangement  for  single-track  excavation, 
roadway  18  feet  wide,  slopes  1  horizontal  to  1  vertical. 

The  use  of  this  table  is  explained  as  follows:  Suppose  the 

center  cut  at  vStation  10  is  1.5  ft.  and  the  center  cut  at 

Station  11  is  3.0  ft.     The  sum  of  these  two  center  cuts, 

1.5 -|- 3.0  =  4.5  ft.     The    mean    or   average    center   cut    at 

4  5 
these  stations  is,   therefore,  -jr-  =  2.25ft.     As  the  nearest 

tenth  is  always  used,  we  will  call  the  average  cut  between 
Stations  10  and  11,  2.2  ft. 

Referring  to  the  table,  we  find  in  the  column  headed 
depth  of  cut  in  feet,  the  figure  2,  and  on  the  same  horizontal 
line,  under  the  column  headed  .2,  we  find  1(54.0,  which  is 
the  number  of  cubic  yards  of  material  to  be  excavated 
between  Stations  10  and  11. 

The  quantities  are  given  for  center  cuts  from  .1  foot  to  60 
feet.  For  cuts  greater  than  60  feet,  the  quantities  are 
calculated  for  only  even  feet. 


RAILROAD   LOCATION. 


859 


1446.  Sections. — The  line  is  divided  into  lengths  of 
one  mile  each,  called  sections,  which  are  numbered  in  regu- 
lar order,  the  first  mile  of  the  line 
being  section  1,  the  second  mile  section 
2,  and  so  on.  At  the  division  points, 
i.  e. ,  where  one  section  ends  and  another 
begins,  posts  are  set  up  with  boards  at- 
tached, facing  in  both  directions,  with 
the  number  of  the  section  towards  which 
they  face  written  in  large  figures.  See 
Fig.  379. 

The  section  boards  enable  one  to 
readily  locate  any  particular  part  of  the 
line. 

1447.  Right  of  Way.— Before 
construction  can  be  commenced,  the  ., 
right  of  way  must  be  secured,  a  matter 
always  attended  by  more  or  less  difficulty. 
The  standard  width  of  right  of  way  is 
100  feet,  though,  in  some  cases,  but  4  rods  or  66  feet  is 
adopted,  with  additional  widths  wherever  needed. 

Where  the  local  needs  for  the  road  are  great,  and  the 
enterprise  popular,  much  right  of  way  is  often  donated,  a 
nominal  sum,  usually  one  dollar,  being  paid  as  considera- 
tion. The  ordinary  mode  of  securing  right  of  way  is  by 
direct  purchase.  The  company  employs  an  agent  specially 
fitted  for  his  business,  who  makes  the  most  advantageous 
bargains  possible  with  the  different  owners.  When  there  is 
failure  to  agree  on  price,  a  common  alternative  is  to  leave 
the  question  to  three  arbitrators,  each  of  the  parties  to  the 
transaction  choosing  one  and  agreeing  together  upon  the 
third.  The  arbitrators  unite  upon  a  valuation-which  the 
contracting  parties  have  agreed  to  accept.  Occasionally,  an 
owner,  taking  advantage  of  the  situation,  attempts  extor- 
tion, in  which  case  the  only  recourse  is  to  the  laxv  of  euii- 
nent  domain.  Articles  of  condemnation  are  taken  out  and 
appraisers  appointed  by  the  court,  who  fix  the  amount  of 


800  RAILROAD   LOCATION. 

compensation.     The  process  is  always  attended  by  expense, 
delay,  and  vexation,  and  should  only  be  a  last  resort. 

1448.  Right  of  Way  Maps. — A  careful  survey  is 
made  of  each  separate  piece  of  property  bought  for  right 
of  way  or  station  grounds,  and  stone  corners  established  for 
future  reference.  These  surveys  should  be  platted  in  a 
"right  of  way"  book  in  the  same  order  in  which  they  occur 
on  the  line,  and  a  copy  of  the  contract  for  and  description 
of  the  property  written  on  the  same  page  or  that  adjoining 
the  plat.  The  plat  should  specify  content,  boundaries, 
corners,  and  any  information  which  may  be  of  future  use. 
A  copy  of  the  contract  and  a  tracing  of  the  plat  is  delivered 
to  the  person  or  persons  from  whom  the  property  is  bought. 

1449.  Specifications. — Specifications  describe  the 
manner  in  which  the  work  of  construction  is  to  be  con- 
ducted and  the  materials  to  be  used  in  structures. 

Specifications  are  of  two  kinds;  \\z.,  gc7ieral,  those  de- 
scribing the  different  general  classes  of  work,  and  special, 
those  referring  to  a  particular  structure  or  other  work 
requiring  special  plans  or  processes.  In  this  work  only 
general  specifications  will  be  given. 


A.,  B.,  &  C.  R.  R. 


GENERAL  SPECIFICATIONS  FOR  GRADING  AND 
BRIDGING. 

1.  Clearing. — The  surface  is  to  be  cleared  the  full 
width  of  right  of  way  and  such  additional  width  as  the 
engineer  in  charge  shall  direct,  of  all  trees,  bushes,  and 
other  perishable  matter. 

2.  Grubbing. — In  cuttings,  and  in  embankments  where 
the  fill  is  two  feet  and  less,  all  trees  and  stumps  between  the 
slope  stakes  must  be  grubbed  out;  where  the  fill  is  more 
than  two  feet,  all  trees  and  stumps  must  be  cut  down  even 
with  the  surface  of  the  ground.  No  payment  will  be  made 
for  grubbing. 


RAILROAD   LOCATION.  861 

3.  Grading. — Under  this  head  will  be  included  all  ex- 
cavations and  embankments  required  for  the  formation  of 
the  roadbed,  side  tracks,  and  station  grounds;  the  founda- 
tion pits  for  bridges,  culverts,  and  cattle-guards;  the  cutting 
of  ditches  and  drains  contiguous  to  the  roadbed;  all  excava- 
tions and  embankments  in  constructing  farm  and  highway 
crossings,  and  in  the  changing  of  channels  for  streams. 

4.  Borrow  Pits. — The  embankment  shall  be  con- 
structed from  material  borrowed  from  the  right  of  way. 
No  embankment  shall  be  constructed  from  material  de- 
posited by  casting  without  special  permission  of  the  engineer 
in  charge.  If  borrow  pits  are  required  outside  the  right  of 
way,  they  shall  be  procured  by  the  railroad  company. 

5.  Provision  for  Settling. — Cuts  and  ditches  shall  be 
measured  in  excavation;  all  other  work  shall  be  measured 
and  paid  for  in  embankment.  The  embankments  shall  be 
made  from  5  to  10  per  cent,  higher  than  the  established 
grades.  This  additional  percentage  is  an  allowance  for 
shrinkage,  and  shall  be  fixed  by  the  resident  engineer.  No 
allowance  for  such  shrinkage  shall  be  made  in  the  estimate. 

6.  Single-Track  Work. — In  single-track  work  the 
roadway  shall  be  eighteen  feet  in  width  at  sub-grade  in  cuts, 
and  fourteen  feet  in  width  on  embankments.  The  side 
slopes  of  earth  cuts  shall  be  one  horizontal  to  one  vertical, 
and  of  rock  cuts  one-quarter  horizontal  to  one  vertical,  un- 
less otherwise  specified  by  the  engineer  in  charge.  The  side 
slopes  for  embankments  shall  be  one  and  one-half  horizontal 
to  one  vertical.  A  berme  six  feet  in  width  shall  be  left 
between  the  slope  stakes  and  the  edge  of  the  borrow  pits. 

7.  Double-Track  Work. — In  double-track  work  the 
roadway  shall  be  twenty-eight  feet  in  width  at  sub-grade  in 
cuts,  and  twenty-four  feet  in  width  on  embankments.  Side 
slopes  of  earth  cuts  shall  be  one  horizontal  to  one  vertical; 
of  rock  cuts,  one-quarter  horizontal  to  one  vertical,  unless 
otherwise  specified  by  the  engineer  in  charge.  The  side 
slopes  for  embankments  shall  be  one  and  one-half  horizontal 


m  RAILROAD   LOCATION. 

to  one  vertical.     A  berme  six  feet  in  width  shall  be  left 
between  the  slope  stakes  and  the  edge  of  the  borrow  pit. 

8.  Borrow  Pits. — A  space  three  feet  in  width  shall  be 
left  between  the  borrow  pits  and  the  right-of-way  lines. 
The  slopes  of  borrow  pits  shall  not  be  steeper  than  one  and 
one-half  horizontal  to  one  vertical,  and  shall  generally  be  of 
such  depth  as  will  secure  proper  drainage. 

9.  Ditches. — All  excavations  shall  be  finished  with  side 
ditches  of  such  dimensions  as  the  engineer  shall  direct,  and 
to  prevent  the  washing  of  slopes,  ditches  shall  be  cut  on  the 
up-hill  side,  such  ditches  to  be  not  less  than  four  feet  from 
the  top  of  the  slope. 

10.  Excavation. — The  classification  for  all  excavated 
material  will  be  as  follows: 

Earth  will  include  clay,  sand,  gravel,  loam,  decomposed 
rock,  and  slate,  and  all  other  matters  of  an  earthy  kind,  how- 
ever hard,  stiff,  or  compact,  and  all  boulders  containing  less 
than  three  cubic  feet  each. 

Loose  rock  will  include  all  stone  and  detached  rock 
found  in  separate  masses,  containing  not  less  than  three 
cubic  feet  nor  more  than  one  cubic  yard;  also,  all  slate, 
coal,  or  other  rock,  soft  or  loose  enough  to  be  removed  with- 
out blasting,  although  blasting  may  be  resorted  to;  also, 
stratified  limestone  ip  layers  eight  inches  thick  and  under, 
separated  by  strata  of  clay. 

Solid  rock  will  include  all  rock  in  masses  of  more  than 
one  cubic  yard  which  can  not  be  removed  without  blasting. 

11.  Foundation  excavation  above  the  general  water 
level  at  the  time  shall  be  excavated  by  the  contractor  and 
paid  for  at  his  grading  prices.  The  residue  of  foundation 
work  will  be  executed  by  the  contractor,  and  paid  for  by 
the  company  at  actual  cost,  with  ten  per  cent,  added  for 
contractor's  supervision,  use  of  tools,  etc.  The  price  per 
yard  bid  for  masonry  will  include  centerings,  scaffoldings, 
and  all  other  expenses  connected  with  the  work,  excepting 
the  foundation  work  above  specified. 


RAILROAD   LOCATION.  863 

12.  Tunnel  Excavation. — The  price  for  tunnel  ex- 
cavation will  include  all  excavation  between  the  portals  of 
the  tunnel  proper,  and  within  the  area  of  the  cross-section, 
as  determined  by  the  engineer,  and  it  will  include  also  all 
temporary  supports,  scaffolding,  etc.  The  area  of  the  cross- 
section  for  tunnel  excavation  will  be  measured  six  inches 
outside  the  wall  and  arch,  and  all  excavation  outside  of  this 
cross-section  will  not  be  paid  for  unless  in  the  opinion  of  the 
engineer  such  irregularities  could  not  be  prevented  by  the 
exercise  of  proper  care  and  judgment  in  excavating,  and 
paid  for  at  such  prices  as  the  engineer  shall  determine, 

13.  Masonry. — Masonry  shall  be  built  according  to 
plans  furnished  by  the  engineer,  and  estimated  and  paid  for 
by  the  cubic  yard.  Masonry  in  which  mortar  is  required  shall 
be  kept  well  wet  while  being  laid,  and  every  stone  shall  be 
clean  and  thoroughly  wet  when  laid.  Arches  shall  be  built 
on  substantial  centers  extending  the  entire  length  of  the 
arch,  and  the  mode  of  construction,  as  well  as  the  plan,  shall 
be  approved  by  the  engineer.  Centers  shall  not  be  removed 
or  loosened  without  the  direction  of  the  engineer.  The 
price  per  yard  shall  in  all  cases  include  the  furnishing  of 
centers,  scaffolding,  and  all  other  cost  and  expense  incidental 
to  the  completion  of  the  work.  All  joints  of  face  walls  of 
masonry  laid  in  mortar  shall  be  suitably  pointed,  and  the 
work  finished  to  the  satisfaction  of  the  engineer. 

Tunnel  Masonry. — The  masonry  for  tunnels  and  all 
bridge  piers  and  abutments  shall  be  of  Rock  Face  Range 
Work.  All  of  the  arch  stones  shall  be  well  and  smoothly 
cut  on  the  beds,  ends,  and  face,  and  shall  be  laid  so  that 
their  beds  shall  be  at  right  angles  to  the  tangent  of  the 
curve.  The  beds  of  each  stone  shall  have  full  and  solid 
bearings,  and  the  joints  shall  be  close  and  straight. 

Walls  and  arches  shall  belaid  in  regular  courses  of  uniform 
thickness.  No  course  shall  be  less  than  four  inches  in  thick- 
ness. The  faces  shall  be  Rock  Face  with  edges  pitched  to 
straight  and  true  lines. 

The  vacancies  behind  tunnel  walls  and  above  tunnel  arches 


864  RAILROAD    LOCATION. 

shall  be  filled  with  concrete  or  dry  packing,  at  the  discre- 
tion of  the  engineer.  All  packing  must  be  well  rammed  in 
place  as  the  work  progresses. 

First-Class  Masonry. — In  all  first-class  masonry  the 
stones  of  each  course  shall  be  gauged  to  the  same  thickness, 
and  after  each  course  is  laid  and  grouted  or  filled  with  mor- 
tar, the  tops  of  the  stones  shall  be  dressed  so  as  to  bring  the 
top  of  the  course  to  a  common  level. 

Stretchers  shall  be  not  less  than  three  feet  in  length,  with 
bed  not  less  than  sixteen  inches.  Headers  shall  be  not  less 
than  eighteen  inches  in  width,  nor  less  than  three  times 
the  thickness  of  the  course  in  length.  Stretchers  and 
headers  should  be  in  the  proportions  of  3  to  1.  All  face 
stones  shall  be  dressed  full  to  the  square  for  their  entire 
length  and  width,  and  shall  be  so  cut  and  laid  as  to  have 
a  full  bearing  for  their  entire  bed.  All  joints  shall  be 
close  and  straight,  and  be  so  broken  as  to  make  a  perfect 
bond. 

Backing  shall  be  of  good-sized  and  well-shaped  stones  and 
so  dressed  that  each  stone  shall  lie  firmly  on  its  bed.  The 
backing  shall  be  laid  with  reference  to  each  succeeding 
course,  affording  good  header  bearers  and  so  bonding  the 
whole  into  one  solid  mass.  All  stones  shall  be  laid  in  mor- 
tar, and  if  the  engineer  shall  so  direct,  the  vertical  joints 
shall  remain  open  until  the  course  is  finished.  All  unfilled 
parts  of  the  wall  shall  be  filled  with  mortar  or  grout.  The 
tops  of  the  walls  shall  be  coped  with  large  broad  stones,  not 
less  than  three  feet  in  length,  the  same  to  be  well-dressed 
on  the  top  and  ends,  and  all  face  joints  pointed  with  good 
mortar. 

Culvert  Masonry. — Arched  and  box  culverts  shall  be 
built  of  good-sized  and  well-shaped  stones,  and  laid  dry 
unless  otherwise  directed  by  the  engineer  in  charge.  Stones 
shall  be  straightened  on  faces  and  ends  with  fair  proportion 
of  headers,  and  laid  with  joints  broken  so  as  to  form  a  com- 
pact and  substantial  body.  Covering  stones  shall  be  of  such 
length  and  thickness  as  the  engineer  in  charge  shall  direct. 


RAILROAD   LOCATION.  8G5 

The  top  courses  of  wing  waits  shall  be  of  wide  stones  with 
good  joints,  so  as  to  form  a  good  and  smooth  coping. 

14.  Pavement. — Between  the  side  walls  and  at  the 
ends  of  culverts  and  bridges  where  required,  paving  will  be 
laid  of  good  smooth  stones  set  on  edge  and  well  fitted,  so  as 
to  make  a  close,  smooth  surface.  Paving  shall  be  of  such 
thickness  as  the  engineer  shall  direct,  and  it  shall  be  secured 
at  ends  and  sides  by  curb  stones  not  less  than  two  feet  in 
depth.  To  prevent  undermining,  broken  stone  shall  be 
deposited  outside  the  curbing.  Paving  will  be  paid  for  by 
the  cubic  yard. 

15.  Mortar  and  grout  shall  be  made  of  clean  sharp 
sand  and  fresh  slacked  lime,  in  the  proportions  of  one  part  of 
lime  to  two  of  sand.  Mortar  shall  be  thoroughly  mixed 
and  allowed  to  stand  until  all  particles  of  lime  are  thoroughly 
slacked.  Hydraulic  cement  to  be  substituted  for  lime  at 
the  discretion  of  the  engineer,  the  difference  in  actual  cost 
to  be  refunded  to  the  contractor.  The  proportion  of  the 
ingredients  of  mortar  and  grout  may  be  varied  at  the  dis- 
cretion of  the  engineer. 

16.  Protection. — When  required  by  the  engineer,  em- 
bankments will  be  protected  by  cribbing  built  of  round  logs 
and  filled  with  stone,  or  riprap  laid  with  beds  at  right  angles 
to  the  slope  of  embankment,  affording  a  close  and  generally 
smooth  surface.  Contractors  shall  hold  themselves  in  readi- 
ness to  perform  such  work  with  promptness  and  dispatch. 
Cribbing  will  be  paid  for  by  the  lineal  foot,  and  riprap  by 
the  cubic  yard — both  to  be  measured  in  place. 

17.  Piling. — Piles  shall  be  of  white  or  burr  oak,  long 
leaf  pine,  or  other  suitable  timber,  sound  and  without  loose 
or  rotten  knots.  They  shall  measure  not  less  than  seven 
inches  in  thickness  at  the  small  end,  and  average  not  less 
than  eleven  in  thickness.  The  bark  must  be  removed  before 
driving. 

18.  Driving. — Piles  must  be  driven  at  the  places  staked 
out  for  them  by  the  engineer  in  charge,  and  they  must  be 


866  RAILROAD   LOCATION. 

driven,  if  the  engineer  so  desires,  to  such  a  depth  that  a 
hammer  weighing  2,000  pounds,  falling  upon  the  pile  from 
a  height  of  twenty  feet,  will  not  sink  the  pile  more  than  one 
inch. 

19.  Timber. — All  timber  shall  be  of  sound,  straight- 
grained  white  or  long  leafed  southern  pine  or  other  suitable 
timber,  free  from  rotten  knots  or  shakes,  and  with  no  sap 
extending  more  than  two  inches  from  any  edge. 

20.  Framing. — The  framing  shall  be  done  in  the  most 
workmanlike  manner  and  in  accordance  with  plans  furnished 
by  the  engineer. 

2L  Inspection. — The  kind  and  quantity  of  all  material 
in  the  work  shall  be  subject  to  the  approval  of  the  engineer 
in  charge.  Timber  shall  be  estimated  in  place  and  paid  for 
by  the  thousand  feet,,  board  measure.  All  iron  used  in 
structures  will  be  paid  for  by  the  pound. 

22.  Montlily  Estimates. — During  the  progress  of  the 
work,  on  or  about  the  first  of  every  month  a  monthly  esti- 
mate shall  be  made  of  the  kind,  quality,  amount,  and  value 
of  work  done  during  the  preceding  month,  eighty-five  per 
cent,  of  which  value  will  be  paid  to  the  contractor  on  or 
about  the  fifteenth  of  said  month,  and  when  the  work  is 
completed  and  accepted  there  shall  be  a  final  estimate  made 
by  the  engineer  of  the  quantity,  character,  and  value  of  the 
entire  work,  according  to  the  terms  of  the  contract,  and  the 
balance,  after  deducting  the  several  monthly  payments,  and 
upon  the  contractor  giving  release  to  the  company  from  all 
claims  or  demands  whatsoever,  will  be  paid  in  full. 

23.  The  contractor  shall  render  an  account  monthly, 
through  the  proper  superintending  engineer,  of  any  extra 
work  which  he  may  have  been  authorized  to  do;  and  to  pre- 
vent disputes  hereafter,  it  is  hereby  understood  that  no  bills 
for  extra  work  will  be  allowed  unless  authorized  and  ordered 
in  writing  by  the  engineer  in  charge,  and  the  bill  for  said 
extra  work  presented  at  the  end  of  the  month  in  which  the 
work  was  done,  and  approved  by  said  engineer. 


RAILROAD   LOCATION.  867 

24.  During  the  progress  of  the  work  and  until  it  shall 
be  completed  and  accepted  by  the  company,  it  shall  be  the 
duty  of  the  contractor,  at  his  own  expense,  to  sufficiently 
guard  and  protect  the  same  by  barriers,  fences,  or  otherwise, 
so  as  to  prevent  travelers  or  other  persons  from  sustaining 
injury  to  themselves  or  property  by  falling  into  any  excava- 
tion or  running  over  any  dangerous  fill  or  embankment,  or 
over  or  against  stumps,  timber,  or  any  material,  or  in  any 
other  way  whatsoever;  and  in  blasting  stone,  the  contractor 
shall  use  the  utmost  precaution  and  care  to  avoid  injuring 
persons  or  property,  and  the  contractor  shall  save  and  keep 
the  company  free  and  harmless  from  the  payment  of  any 
damage  for  injury  to  persons  or  property  arising  from  any 
malfeasance  or  negligence  of  the  contractor  or  of  any  of  his 
sub-contractors,  agents,  or  servants. 

25.  The  contractor  shall  not  let  or  transfer  his  contract 
or  any  part  of  it,  or  withdraw  his  personal  attention  there- 
from, without  the  consent  of  the  engineer. 

26.  The  contractor  shall  put  on  and  maintain  night 
forces  at  such  points  and  to  such  extent  as  the  engineer  shall 
direct. 

27.  In  all  disputes  the  decision  of  the  engineer  shall  be 
final. 

28.  By  engineer  is  meant  the  chief  engineer. 

1450.  Advertising  for  "Work. — A  classified  estimate 
is  made  of  the  amount  of  work  in  each  section,  and  the  road 
is  advertised  for  contract.  These  advertisements  name  a 
date  for  the  opening  of  bids.  Contractors  are  provided  with 
a  printed  copy  of  the  general  specifications  and  of  the  esti- 
mated quantities  in  each  section,  and  are  allowed  to  take 
such  notes  as  they  may  require  from  the  map  and  profile. 
In  walking  over  the  line  they  can  readily  locate  any  par- 
ticular section  from  the  section  boards. 

1451.  Reservations. — The  company  should  invari- 
ably reserve  the  right  to  reject  any  or  all  bids,  in  order  that 


8G8  RAILROAD    LOCATION. 

they  may  shut  out  irresponsible  men  or  prevent  a  combina- 
tion of  contractors  from  charging  exorbitant  prices  for 
work. 

1452.  Bond. — Contractors  should  be  required  to  fur- 
nish a  bond  signed  by  two  responsible  parties  to  insure  the 
proper  fulfilment  of  their  contract.  This  bond  is  usually 
to  the  amount  of  ten  per  cent,  of  the  estimated  cost  of  the 
work  undertaken.  The  contract  specifies  the  date  on  or 
before  which  the  contractor  shall  complete  the  work,  and 
often  specifies  a  forfeit  to  be  imposed  in  case  of  any  default 
on  the  part  of  the  contractor  to  fulfil  the  conditions  of  his 
contract. 


RAILROAD  CONSTRUCTION. 


1453.  The  Engineer  Corps. — The  engineer  corps  in 
charge  of  construction  differs  in  organization  from  that  in 
charge  of  location.  In  general,  when  construction  is  com- 
menced, it  is  prosecuted  with  vigor  throughout  the  entire 
line,  and,  as  the  work  requires  constant  inspection,  the 
force  of  engineers  is  considerably  augmented. 

1454.  Subdivisions  of  the  Line. — The  entire  line 
is  divided  into  sections  of  about  30  miles  each,  called  divi- 
sions, each  division  being  placed  in  charge  of  a  division 
engineer.  The  divisions  are  further  divided  into  lengths 
of  about  10  miles  each,  called  residencies.  Each  residency 
is  placed  in  charge  of  a  resident  engineer. 

1455.  The  Division  Engineer,  His  Authority 
and  Duties. — The  division  engineer  has  general  charge  of 
an  entire  division  and  is  directly  accountable  to  the  chief 
engineer,  from  whom  he  receives  general  orders  relating 
to  the  work  of  his  division.  He  should  go  over  his  entire 
division  twice  each  week,  giving  particular  directions  to  the 
resident  engineers  for  the  conduct  of  the  work  and  main- 
taining a  general  supervision  of  the  whole.  His  office 
should,  if  possible,  be  so  situated  as  to  afford  prompt  mail 
service.  Telegraphic  communication  with  the  chief  engineer 
is  important,  though  not  always  possible.  Plans  of  all  the 
important  structures  on  a  division,  excepting  large  bridges, 
are  made  at  the  division  office  and  forwarded  to  the  chief 
engineer  for  approval.  The  monthly  estimates  made  by  the 
resident  engineers  of  his  division  are  inspected  by  the  divi- 
sion engineer,  a  careful  record  of  them  kept  at  his  office, 
and  forwarded  by  him  to  the  chief  engineer  for  approval. 


870  RAILROAD   CONSTRUCTION. 

1456.  The  Resident  Engineer,  His  Corps,  and 
Their  Duties. — The  corps  in  charge  of  each  residency, 
comprises  the  resident  engineer,  instrument  man,  rodman, 
tapeman,  and  axman.  The  resident  engineer  has  immediate 
charge  of  all  work  on  his  residency,  a  profile  of  which  is 
given  him  with  the  grade  lines  drawn  upon  it,  with  the 
gradients  and  compensation  for  curvature  clearly  stated. 
At  each  watercourse  shown  in  the  profile,  a  brief  descrip- 
tion is  written,  giving  the  character  and  dimensions  of  the 
structure  required  at  that  place.  He  is  given  a  copy  of  the 
specifications  which  are  to  guide  him  in  making  a  proper 
inspection  of  the  work.  A  suitable  office  is  provided  him  at 
or  as  near  the  middle  of  his  residency  as  possible,  and  fur- 
nished with  drawing  table,  drawing  materials,  field  books, 
pads,  and  official  stationery.  A  horse  and  strong  two-seated 
buckboard  are  an  important  part  of  his  outfit,  especially 
when  in  thickly  settled  country,  where  the  line  of  road  is 
readily  accessible  from  public  highways. 

The  first  duty  of  the  resident  engineer  is  to  check  the 
alinement  and  levels  on  the  line  of  his  work,  transferring 
bench  marks  from  trees  or  rocks,  which  are  liable  to  be  dis- 
turbed, to  permanent  objects  far  enough  from  the  center 
line  to  be  outside  of  the  slope  stakes. 

1457.  Setting  Slope  Stakes. — His  next  work  is  set- 
ting slope  stakes,  commonly  called  cross-sectioning, 
which  consists  of  setting  stakes  in  the  ground  at  the  points 
which  will  mark  the  top  of  the  cut  or  foot  of  the  slope  of  the 
finished  roadway.  The  following  dimensions  are  suitable 
for  cross-section  stakes:  Length,  2  feet;  width,  2  inches, 
and  thickness,  1  inch.  They  should  be  planed  on  one  side 
to  admit  of  easy  marking,  and  sharpened  for  driving.  In  a 
country  of  average  smoothness,  the  level,  rod,  and  tape 
are  used  in  locating  slope  stakes;  but  in  very  rough  locali- 
ties, the  Y  level  is  used  to  carry  the  continuous  line  of 
levels,  while  the  side  elevations,  from  which  the  slope  stakes 
are  located,  are  determined  by  means  of  the  hand  level 
and  rods. 


RAILROAD   CONSTRUCTION. 


871 


^  1^  8 


The  process  of  setting  slope  stakes  is  illustrated  in  Figs. 
380  and  381.  In  Fig.  380,  the  elevation  of  the  grade  is 
103.0  feet.  The  height  of  in- 
strument A  is  97.5  feet,  and, 
hence,  the  instrument  is  5.5 
feet  below  grade.  The  rod  read- 
ing at  the  center  line  is  CO  feet, 
hence,  the  surface  of  the  ground 
at  the  center  line  is  below 
grade,  i.  e.,  there  must  be  a 
fill,  the  amount  of  which  is 
made  up  of  two  quantities,  viz. : 
First,  the  difference  between 
the  elevation  of  grade  and  the 
height  of  instrument ;  and,  sec- 
ond, the  rod  reading  at  the 
center  line. 

The  first  of  these  quantities  is 
5. 5  feet,  the  second  6.0  feet,  and 
their  sum,  11.5  feet,  is  the 
amount  of  the  fill  at  center.  If 
this  cross-section  is  taken  at  a 
full  station,  there  will  already 
be  a  stake  in  place,  and  the  Jil/ 
is  marked  on  the  back  of  the 
stake  F.  11.5.  If  the  section  is 
taken  at  an  intermediate  point, 
i.  e.,  a  sub-station,  say  20  +  50, 
the  center  line  is  located  by  rang- 
ing in  from  the  stakes  at  the 
regular  stations  and  the  stake 
is  marked  20  -j-  50  on  one  side 
and  the  fill,  F.11.5,  on  the  other 
side,  and  the  stake  driven  with 
the  numbering  facing  Station 
20.  The  s/ope  stakes  are  located  by  holding  the  leveling  rod 
where,  in  the  judgment  of  the  rodman,  the  foot  of  the 
slope  of  the  completed  embankment  will  be.     In  Fig.  380, 


872 


RAILROAD   CONSTRUCTION. 


the  rod  reading  at  the  right  of  the  center  line  is  9.5  feet, 
which,  added  to  5.5  feet,  the  difference  between  the  height 
of     instrument     and  ^ 

grade,  gives  a  fill  of  «; 

15  feet.  The  natural 
slope  of  earth  is  one 
and  one-half  horizon- 
tal to  one  vertical, 
called  a  slope  of  1^ 
to  1.  Therefore,  in 
a  fill  of  15  feet,  the 
foot  of  the  slope  will 
be  1^  times  15,  which 
is  22.5  feet  from  the 
top  of  the  slope,  to 
which  must  be  added 
one-half  the  width  of 
the  roadway,  viz.,  8 
feet,  making  30.5 
feet  from  the  center 
line.  The  rod  is  ac- 
cordingly held  at  30.5 
feet  from  the  center 
line.  If  the  rod  read- 
ing at  this  distance 
is  the  same,  i.  e. ,  9.5 
feet,  it  marks  the 
foot  of  the  slope,  and 
a  stake  marked  F. 
15.0  is  driven  in  the 
place  of  the  rod. 
Usually  the  rod  will 
not  read  exactly  the  * 
same  when  held  at 
the  calculated  dis- 
tance, and  another  calculation  will  be  necessary,  two  trials 
generally  proving  sufficient.  In  Fig.  381,  the  right  slope 
stake  is  fixed  in  the   same   way.     The  left   slope   stake   is 


-Fill  16:2- 


RAILROAD   CONSTRUCTION. 


873 


located  by  means  of  rods  and  a  hand  level.  First,  a  point 
C  is  found  where  the  line  of  sight  from  the  level  A  cuts 
the  surface  of  the  ground.  A  cross-section  rod,  which  is 
similar  to  a  transit  pole,  is  held  at  this  point,  which  is 
5.2  feet  below  grade.  At  5.2  feet  above  C,  a  rod  is  held  in 
a  horizontal  position,  and  the  point  D  where  it  meets  the 
ground  marked  by  a  stake.  This  point  is  at  grade,  i.  e., 
where  the  plane  of  grade  cuts  the  ground.  The  stake  is 
marked  by  two  ciphers  0.0,  and  its  location  recorded  in  the 
note  book.  By  means  of  the  rods,  the  left  slope  stake  at£"is 
located.  As  the  left  slope  is  in  excavation,  the  left  half  of 
the  roadway  will  be  one  foot  greater  in  width  than  the  right 
half,  viz.,  9  feet.  As  the  slopes  in  excavation  are  but  one 
horizontal  to  one  vertical,  called  a  slope  of  1  to  1,  the  dis- 
tance of  the  slope  stake  from  the  center  line  is  the  sum  of 


sta.eo 


Fig.  382. 


one-half  the  width  of  the  roadway,  viz.,  9  feet,  and  the  depth 
of  cutting.  In  Fig.  381,  the  cut  is  6.8  feet;  consequently, 
the  slope  stake  is  set  at  9  +  6.8  =  15.8  feet  from  the  center 
line.  When  the  cross-section  is  irregular,  intermediate 
readings  are  taken  as  shown  in  Fig.  382. 

In  this  section,  besides  finding  the  center  fill,  6.8  feet  at 
A,  and  the  fill  14.4  feet  at  foot  of  right  slope  at  B,  and  a  fill 
of  3.8  feet  at  C  at  foot  of  left  slope,  intermediate  read- 
ings are  taken  at  D  and  E  where  the  slope  of  the  cross- 
section  changes.  These  readings  are  recorded  in  the  note 
books,  but  no  stakes  are  driven  at  the  points  of  change  of 
slope. 


874 


RAILROAD   CONSTRUCTION. 


1458.  Form  of  Cross-Section  Notes. — The  levels 
are  carried  continuously  from  bench  mark  to  bench  mark, 
the  level  notes  being  recorded  on  the  left-hand  page  of  the 
note  book  and  the  cross-section  notes  recorded  on  the  right- 


c 

o 

1 

c 
•S 

o 

Pi 

c 

1— 1 

> 

>-  2 

c 

u 

o 

4-> 
o 

■(-> 
C 

O 

C 

Left  Line. 

Right  Line. 

20 
40 
60 

6.0 

2.7 

97.5 
114.8 

• 

91.5 
112.1 

103.0 
120.0 

11.5 

7.9 
6.8 

F.  9.0 

21.5 

C.G.8     0.0 

15.8     5.0 

F.3.8   F.6.8 

F.15.0 

30.0 

F.16.2 

32.3 

F.7.0F.14.4 

13.7        8.0 

8.0     29.6 

hand  page.  The  above  form  of  cross-section  notes  is  simple 
and  complete,  and  contains  the  notes  for  Figs.  380,  381,  and 
382. 

The  cross-section  notes  are  recorded  in  the  form  of  frac- 
tions, the  amount  of  cut  or  fill  being  the  numerator  of 
the  fraction,  and  the  distance  of  the  slope  stake  from  the 
center  line,  called  the  side  distance,  being  the  denomi- 
nator. 

It  will  be  seen  in  comparing  the  notes  for  Station  20  with 
Fig.  380  that  the  rod  reading  at  the  center  stake  is  6.0  feet, 
which  gives  a  center  fill  of  11.5  feet.  The  figure  shows  at 
the  foot  of  the  right  slope  a  rod  reading  of  9.5  feet.  The  in- 
strument man  instead  of  determining  the  elevation  of  the 
ground  at  this  point  by  subtracting  the  rod  reading  from 
the  height  of  instrument  and  then  calculating  the  fill  by 
subtracting  the  elevation  of  the  surface  of  the  ground  from 
the  calculated  grade  for  that  station,  calculates  the  fill  in 
this  way.  If  a  rod  reading  of  G.O  feet  gives  a  fill  of  11.5 
feet,  a  rod  reading  of  9.5  feet  must  require  as  much  more 
filling  than  11.5  feet  as  9.5  feet  \%  greater  \h2in  6.0  feet.   The 


RAILROAD   CONSTRUCTION. 


875 


«5l 

or 


O 

"S^" 


*« 


«- 
«■ 

•5" 


-  -*H-  2   6 


-C- 


difference  9.5  —  6.0  =  3.5  feet;  11.5  +  3.5  = 
15.0  feet,  i,  e.,  a  rod  reading  of  9.5  feet 
requires  a  fill  of  15.0  feet. 

In  the  notes  for  Sta.  GO,  corresponding  to 
Fig.  382,  it  will  be  observed  that  the  inter- 
mediate readings  taken  at  D  and  £  are  re- 
corded in  the  same  order  in  which  they  are 
taken.  The  calculations  of  the  side  dis- 
tances are  simple  problems  in  mental  arith- 
metic, and,  with  a  little  practice,  they  can 
be  made  with  great  rapidity.  A  tape 
especially  adapted  to  cross-section  work  is 
graduated  on  both  sides,  one  side  giving 
the  varying  fills  from  1  foot  to  28  feet,  and 
the  other  side  being  graduated  to  feet  and 
tenths  of  a  foot.  Fig.  383  illustrates  the 
principle  upon  which  the  tapes  are  made. 

As  shown  in  the  figure,  the  eight-foot 
mark  on  the  right  side  of  the  tape  corre- 
sponds with  the  zero  mark  on  the  reverse 
side.  The  reason  for  this  is  that,  whatever 
the  fill,  the  slope  stake  must  be  placed  at 
least  eight  feet  from  the  center  line  in 
order  to  afford  sufficient  width  for  the  road- 
way. Each  division  representing  tenths  of 
feet  of  filling  is  equivalent  to  1^  tenths  of 
feet  of  lineal  measurement,  that  is,  a  fill  of  1 
foot,  as  marked  on  the  reverse  side  of  the 
tape,  corresponds  to  the  division  9.5  feet 
on  the  right  side  of  the  tape.  In  using  the 
tape,  a  man  stands  at  the  center  stake 
holding  the  tape  case.  The  rodman  holds 
the  end  of  the  tape  besides  carrying  the 
rod.  The  man  at  the  center  stake  lines  in 
the  rodman,  that  is,  he  places  him  as 
nearly  at  right  angles  to  the  center  line 
as  he  can  estimate  by  the  eye.     The  rodman 


876  RAILROAD   CONSTRUCTION. 

first  holds  the  rod  at  where  he  judges  will  be  the  foot  of 
the  slope.  The  instrument  man  calculates  the  fill  and 
calls  the  amount  of  the  fill  to  the  tapeman,  who  finds  on 
the  reverse  side  of  the  tape  the  numbers  corresponding  to 
the  given  fill,  and  holds  the  tape  at  that  point  on  the  center 
stake,  causing  the  rodman  to  approach  or  recede  from  the 
center  line  according  as  his  calculation  has  differed  from  the 
true  one.  Again,  a  rod  reading  is  taken  and  the  amount  of 
the  fill  called  out,  and  the  corresponding  fill  being  found  on 
the  tape,  the  rodman  is  checked  again  by  the  level.  Two 
trials,  unless  the  slopes  are  very  irregular,  will  generally  be 
sufficient. 

1459.  Clearing. — All  trees,  logs,  and  bushes  are 
cleared  from  the  right  of  way.  Ordinarily,  this  work  is  let 
by  contract  at  a  fixed  price  per  acre  to  experienced  woods- 
men. A  skilful  axman  will  fall  and  trim  more  trees  in  one 
day  than  five  inexperienced  men,  and  the  work  will  be  bet- 
ter done.  The  resident  engineer  should  require  the  con- 
tractor to  clear  the  right  of  way  immediately  after  his 
taking  charge  of  the  work,  as  the  work  of  staking  out  must 
be  deferred  until  after  the  clearing  is  completed.  As  all 
timber  on  the  right  of  way  belongs  to  the  railroad  company, 
the  resident  engineer  should  require  the  contractor  to  avoid 
unnecessary  destruction  of  merchantable  timber  while  clear- 
ing the  right  of  way.  Timber  suitable  for  cross-ties  should 
be  worked  up  at  once,  the  ties  being  piled  in  safe  places  and 
in  such  form  as  will  admit  of  rapid  seasoning.  Logs  large 
enough  for  boards  and  square  timber  are  piled  well  out  of 
reach  of  the  work  of  construction.  Clearing  will  cost  from 
$20  to  $50  per  acre. 

1460.  Grubbing.  — Grubbing  includes  the  removing 
of  all  trees  and  stumps  lying  within  the  slope  stakes  in  cut- 
tings and  in  embankments  where  the  fill  is  two  feet  or  less. 
Formerly  all  trees  and  stumps  were  grubbed  by  digging 
about  the  stump  and  exposing  the  roots,  which  were  cut  off 
with   an   ax.     After  the  large   roots  were    severed,   a  long 


RAILROAD   CONSTRUCTION.  877 

lever  was  used  to  complete  the  work  by  overturning  the 
stump.  A  better  method  succeeded  this  very  slow  and 
expensive  work  of  grubbing.  The  trees  were  left  standing 
and  as  soon  as  the  large  roots  were  cut,  horsepower  was 
employed  as  follows:  A  strong  rope  was  fastened  to  the 
trunk  high  above  the  ground.  A  strong  team  (often  two 
teams)  were  then  hitched  to  the  rope  at  a  safe  distance 
from  the  tree.  The  leverage  gained  was  great,  and  the  tree 
could  often  be  overset  with  half  or  even  less  than  half  the 
grubbing  that  was  required  by  the  older  process.  In  mod- 
ern practice  dynamite  is  almost  exclusively  employed.  The 
trees  are  first  felled  and  their  trunks  and  branches  removed. 
A  round-pointed  bar  of  steel  2  inches  in  diameter  is  driven 
at  an  angle  beneath  the  stump,  penetrating  far  enough  to 
bring  the  explosive  directly  beneath  the  stump.  The  bar  is 
then  removed,  and  the  hole  loaded  with  dynamite,  precisely 
as  in  blasting  rock.  A  little  experience  will  enable  one  to 
gauge  the  amount  of  the  charge.  The  execution  of  the 
powder  is  thorough,  generally  blowing  the  stump,  together 
with  the  roots,  completely  out  of  the  ground  and  splitting 
the  stump  into  several  pieces,  which  greatly  facilitates  the 
work  of  handling  them.  In  grubbing  stumps  with  dyna- 
mite, the  gain  in  first  cost  over  other  methods  is  great,  but 
the  gain  in  time  is  greater  still. 

Grubbing  is  sometimes  paid  for  by  the  acre,  oftener  by 
the  stump,  and  in  some  cases  the  cost  of  grubbing  is  in- 
cluded in  the  price  paid  for  excavation. 

As  stated  in  Art.  1433,  the  clearing  of  the  right  of  way 
will  often  afford  opportunity  for  slight  changes  in  the  line 
which  will  considerably  reduce  the  cost  of  construction.  It 
is  important  that  the  work  of  cross-sectioning  be  completed 
at  the  earliest  possible  date  after  construction  has  com- 
menced, as  the  demands  upon  the  engineer's  time  multiply 
when  construction  is  well  under  way.  Where  the  line 
traverses  open  and  timbered  country  in  about  equal  propor- 
tions, the  cross-sectioning  on  the  open  stretches  can  be 
pushed  while  the  clearing  is  being  done;  in  this  manner  the 
work  can  be  kept  well  in  hand. 


878  RAILROAD   CONSTRUCTION. 

CULVERTS. 

1461.  Classification  of  Culverts. — Culverts    are 

of  three  classes,  viz.,  box,  tile,  and  arched.  The  dimen- 
sions of  a  culvert  will  depend  upon  the  amount  of  water  to 
be  discharged.  This  amount  will  depend  upon  the  area 
and  character  of  the  water  shed.  The  engineer  can  approxi- 
mately determine  this  area  either  from  an  inspection  of 
county  maps  or  from  personal  examination  of  the  country. 
Local  records  of  high  water  will  be  of  great  service  to  him. 
Culverts  should  always  be  made  large  enough  to  meet  the 
requirements  of  the  greatest  freshets.  The  following  for- 
mula is  used  by  some  engineers  in  determining  the  area  of 
a  culvert  opening  : 

A=c^^,  (102.) 

in  which  A  is  the  area  of  the  opening  of  the  culvert  in 
square  feet,  M  is  the  drainage  area  in  acres,  and  c  the  vari- 
able coefficient  depending  upon  the  nature  of  the  country, 
1.6  being  used  for  compact  hilly  ground,  1  for  comparatively 
level  ground,  and  being  raised  to  4  for  abrupt  rocky  slopes. 
For  example,  under  average  conditions,  a  drainage  area 
of  200  acres  with  a  coefficient  of  1.6  will  give  the  following 
cross-section  area  for  a  culvert : 

A  =  l.Gi/200-  22.62  sq.  ft. 

In  this  situation  a  double-box  culvert  would  be  suitable, 
with  openings  three  feet  in  width  and  four  feet  in  height, 
separated  by  a  wall  two  feet  in  thickness. 

1462.  Box  Culverts. — Foundations  will  be  prepared 
as  follows:  Excavate  a  pit,  including  the  entire  area  of  the 
opening  and  the  side  walls,  to  a  depth  of  1  foot.  Cover 
this  area  with  a  paving  of  stones  set  on  edge  1  foot  in 
depth,  with  a  curb  two  feet  in  depth  at  each  face  of  the 
drain,  and  start  the  walls  on  this  paving.  The  paving,  after 
being  laid,  should  be  well  rammed,  in  order  to  afford  a  firm 
foundation  for  the  superstructure.  If  the  fall  of  the  drain 
does  not  exceed  9  inches,  drop  the  upper  end  to  a  level  with 
the  lower  end.     When    the    fall  is  greater   than  9  inches, 


RAILROAD   CONSTRUCTION. 


879 


make  a  sufficient  number 
of  drops  of  9  inches  each 
to  equal  the  difference  in 
the  elevation  of  the  two 
ends  of  the  drain. 

At  each  drop,  place  a 
cross-sill  2  feet  in  depth. 
Box  culverts  are  not  made 
of  greater  span  than  3  feet. 
When  a  wider  opening  is 
required,  a  double-box  cul- 
vert is  built  with  a  division 
wall  2  feet  in  thickness. 

A  general  plan  for  a 
single-box  culvert  is  shown 
in  Fig.  384.  The  distance 
marked  10  ft.  is  termed 
the  height  of  the  embank- 
ment at  center  line. 

Box  culverts  are  gen- 
erally constructed  of  dry 
rubble  masonry.  The 
stones  in  the  abutments 
(also  called  side  walls,  and 
having  a  height  of  3  ft.,  in 
Fig.  384)  should  be  of 
good  size,  faced  with  beds 
roughly  dressed  and  laid 
with  joints  well  broken. 
Binders  reaching  through 
from  face  to  face  of  wall 
must  be  used  in  sufficient 
numbers  to  insure  a  com- 
pact and  stable  structure. 
Covering  flags  (4  ft.  6  in. 
wide  and  1  ft.  thick,  in 
Fig.  384)  must  be  of  com- 
pact stone  free  from  seams 


,20'        121. 


'I2f 

■t 


880  RAILROAD   CONSTRUCTION. 

and  with  faces  dressed  so  as  to  insure  a  complete  cov- 
ering. Mortar  is  used  at  the  discretion  of  the  engineer 
in  charge.  The  parapet,  1  ft.  thick,  is  laid  on  the  covering 
flags. 

In  soft,  marshy  soils,  a  1-foot  paving  will  not  afford  a  se- 
cure foundation,  especially  if  quicksand  be  present.  A  pit 
2  feet  in  depth  and  filled  with  stone,  leaving  only  sufficient 
depth  for  the  1-foot  paving,  and  well  rammed,  will,  together 
with  the  paving,  bear  any  ordinary  box  culvert.  In  wet, 
boggy  soils,  a  secure  foundation  may  be  obtained  by  exca- 
vating a  pit  of  double  the  area  of  the  superstructure  to  the 
depth  of  2  feet  and  laying  a  course  of  logs  of  uniform  size 
over  the  entire  bottom  of  the  pit.  A  layer  of  broken  stone 
is  then  spread  over  the  logs  of  sufficient  depth  to  secure  a 
uniformly  level  surface.  The  paving  is  laid  upon  this 
surface,  and  the  foundation  is  then  in  readiness  for  the 
abutments. 

Rule  I.— To  Lay  Out  a  Box  Culvert  on  the  Ground.— 
Take  the  height  of  the  top  of  the  parapet  from  the  height  ,of 
the  embankment  at  the  center  line.  With  this  difference  as 
height  of  embankme7it,  find  the  side  distance  as  in  setting 
slope  stakes.  To  these  side  distances  add  18  inches,  and  if  the 
embankment  is  10  feet  in  height  or  over,  add  I  inch  on  each 
end  for  each  foot  in  height  above  the  parapet. 

The  covering  flags  are  1  foot  in  thickness  and  the  parapet 
1  foot  in  height,  making  the  top  of  the  parapet  2  feet  above 
the  top  of  the  abutment  or  side  walls.  The  height  of  the 
parapet  is,  therefore,  the  height  of  side  walls  -|-  2  feet.  The 
thickness  of  side  walls  must  never  be  less  than  2  nor  more 
than  4  feet  in  thickness. 

Rule  U.  — To  Find  the  Length  of  Wing  Wails.  — Add  to 

the  height  of  side  tea  I  Is  the  thickness  of  the  covering  fiags. 
One  and  a  half  times  this  sum  plus  2  feet  will  give  the  dis- 
tance from  the  inside  face  of  the  side  wall  to  the  end  of 
tving. 

The  wing  walls  (marked  8  ft.  long,  in  Fig.  384)  must  be 
parallel  to  the  center  line  of  the  road. 


RAILROAD   CONSTRUCTION.  881 

Example. — The  roadway  is  16  feet  in  width,  the  height  of  the 
embankment  at  the  center  line  is  22  feet,  the  abutments  are  4  feet  in 
height,  the  covering  flags  1  foot  thick,  the  parapet  is  1  foot  in  height ; 
what  is  (a)  the  distance  from  the  center  line  to  end  of  abutment  wall, 
and  (d)  the  distance  from  face  of  abutment  wall  to  end  of  wing  wall  ? 

Solution. — (a)  Applying  rule  I,  we  have  22  —  (4  +  2)  =  16. 
16  X  H  +  8  4-  1  ft.  6  in.  +  1  ft.  4  in.  =  34  ft.  10  in.     Ans. 

((5)  Applying  rule  II,  we  have  4  +  1  =  5.    5  X  li  +  2  =  9ft.  6  in.     Ans. 

1463.  — Tile    Culverts.  — In    localities  where    stone    is 

scarce  and  costly,  culvert  pipe  furnishes  an  economical 
and  efficient  substitute.  Culvert  pipe  is  made  of  clay,  which 
is  subjected  to  a  high  degree  of  heat,  when  it  is  known  as 
vitrified  pipe.  The  manufacture  of  culvert  pipe  is  carried 
on  extensively  in  most  of  the  chief  American  cities,  the 
range  in  sizes  being  sufficient  to  meet  all  requirements. 
The  pipes  vary  in  length  from  24  to  30  inches,  and  in  di- 
ameter from  12  to  24  inches.  They  are  fitted  with  socket 
or  bell  joints  similar  to  those  on  cast-iron  water  pipes. 

The  thickness  of  the  shell  is  -^^  the  diameter  of  the  pipe, 
and  the  width  of  the  socket  ^  the  diameter.  The  pipe  is 
laid  on  a  concrete  foundation  with  sufficient  fall  to  prevent 
water  from  standing  in  the  pipes.  A  shallow  pit  is  dug  to 
receive  the  concrete,  the  pipes  being  laid  as  soon  as  the  con- 
crete is  in  place  and  brought  to  a  grade.  The  pipes  are 
laid  with  joints  of  cement  mortar,  and  covered  with  concrete 
to  one-half  their  height;  the  latter  are  held  in  place  by  side 
boards,  secured  by  banking  with  earth  or  by  stakes  driven 
in  the  ground.  The  concrete  affords  a  secure  foundation 
and  prevents  leaking  at  the  joints,  which  is  the  chief  cause 
of  failure  of  pipe  culverts  with  earth  foundations. 

The  parapet  walls  are  of  rubble  masonry  laid  in  cement 
mortar,  and  carried  far  enough  below  the  bottom  of  the 
pipe  to  prevent  undermining.  In  alluvial  soils,  such  as  are 
traversed  by  many  of  our  western  lines,  it  is  frequently 
necessary  to  carry  the  parapet  walls  to  a  depth  of  six  and 
even  eight  feet  to  guard  against  the  undermfning  of  the 
embankment.  The  parapet  walls  need  not  be  built  until 
after  the  completion  of  the  road,  when  the  stone  may  be 


882 


RAILROAD   CONSTRUCTION. 


hauled  by  construction  trains,  thereby  saving  the  great  cost 
of  transporting  building  stone  by  teams.     A  general  plan 


C^ 


Wii^H-:.)-] 


:o5   J       Ql  \^A^-       ^^^ 


of  pipe  culvert  is  given  in  Fig.  385.  When  a  single  pipe  is 
not  sufficient  to  pass  all  the  water,  two  or  more  pipes  are 
placed  side  by  side,  with  concrete  well  rammed  between. 


RAILROAD   CONSTRUCTION.  883 

1464.  Open  "Water  Culverts. — These  are  generally 
of  2  feet  span,  with  walls  2  feet  thick,  and  of  not  greater 
depth  than  3  feet.  The  foundation  is  of  12-inch  paving 
placed  as  in  foundations  of  box  culverts.  The  walls, 
directly  under  the  stringers,  should  be  capped  with  large 
well-finished  stones,  so  as  to  afford  good  bearings  for  the 
stringers,  and  properly  distribute  the  loads  of  passing  trains. 
Both  stringers  and  cross-ties  should  be  of  sawed  timber. 

1465.  Cattle  Guards. — These  are  placed  on  each  side 
of  a  public  road  crossing  when  the  crossing  takes  place  at 
grade.  Formerly  they  were  built  like  open  culverts,  with 
spans  of  from  3  to  5  feet  and  from  3  to  4  feet  in  depth.  The 
abutment  walls,  upon  which  the  wooden  track  stringers 
were  laid,  were  from  2  to  2^  feet  in  thickness.  The  rails 
were  laid  directly  upon  the  stringers,  thus  dispensing  with 
cross-ties  and  leaving  the  space  between  the  rails  and  abut- 
ments entirely  open.  Although  possible  for  stock  to  get 
into  these  pits  it  was  almost  impossible  for  them  to  get  out, 
and  they  often  proved  a  cause  of  instead  of  a  protection 
against  accident. 

The  modern  cattle  guard  dispenses  with  both  masonry 
and  excavation.  It  consists  of  two  strips  of  3-inch  plank 
laid  on  cross-ties  at  a  distance  apart  of  8  feet.  Triangular 
strips  of  either  wood  or  iron  laid  parallel  to  the  rails  are 
spiked  to  these  pieces  of  plank,  completely  covering  the 
space  between  the  rails  excepting  space  for  the  wheel  flanges. 
A  space  2  feet  in  width  outside  the  rails  is  similarly  covered, 
the  whole  closely  resembling  a  gridiron,  which  is  the  name 
given  to  this  form  of  cattle  guard.  It  is  quickly  and  cheaply 
made  and  thoroughly  efficient. 

1466.  Open  Passage  W^ays. — These  are  passage 
ways  for  public  roads  which  cross  the  railroad  below  grade. 
The  walls  in  part  serve  the  purpose  of  retaining  walls,  and 
should  have  a  thickness  at  their  base  of  about  y%-  of  their 
height.  The  coping  of  the  walls  is  arranged  in  the  form  of 
steps,  as  shown  in  the  general  plan  of  highway  culvert;  see 
Fig.  386.     The  height  A  B  oi  the  embankment  is  15  feet. 


884 


RAILROAD  CONSTRUCTION. 


The  steps  CD,  etc., 
are  so  arranged  that 
the  natural  slope  E  F 
of  the  embankment 
will  just  touch  the 
back  of  the  steps. 
The  steps  are  not  car- 
ried down  to  the  level 
of  the  ground,  but 
stop  at  G  where  the 
wall  has  a  height  be- 
tween 4  and  5  feet. 
The  section  shows  the 
thickness  of  the  walls, 
which  are  2^  feet 
thick  on  the  line  of 
slope  where  the  steps 
chow.  The  thickness 
at  the  base  is  at  all 
points  about  ^  of 
the  height  of  the 
embankment  at  that 
point,  giving  a  thick- 
ness of  about  G  feet 
where  the  embank- 
ment attains  its  full 
height,  and  finishing 
at  the  top  with  a 
thickness  of  2^  feet. 
The  back  of  the  wall 
is  indicated  by  the 
line  77  A".  The 
stringer  L  consists 
of  two  timbers  8 
inches  wide  by  IG 
inches  deep  by  17 
feet  in  length,  sep- 
arated   by    cast-iron 


RAILROAD   CONSTRUCTION.  885 

spools  M,  and  called  a  packed  stringer.  The  stringers 
rest  on  wooden  bed-plates  N^  N^  12  inches  wide  by  3  inches 
thick,  and  are  notched  down  1  inch  on  the  bed-plates. 
They  are  spaced  1  ft.  8  in.  from  the  center  line  of  the  track, 
and  are  held  in  place  by  a  strut  (7,  3  in.  by  12  in,  by  3  ft. 
4  in.  Stringer  bolts  P  oi  \  in.  round  iron  pass  through  both 
stringers,  one  on  each  side  of  the  strut,  and  are  fastened  with 
nuts  fitted  with  cast  washers.  The  cross-ties  (2?  8  in.  wide 
by  7  in.  deep,  are  spaced  18  in.  between  centers  and  notched 
down  1  in.  on  the  stringers.  The  guard-rail  7?  is  7  in.  by 
7  in.  bj'  17  ft.,  and  notched  down  1  in.  on  the  cross-ties  and 
bolted  to  every  fourth  or  fifth  cross-tie  with  \  in.  bolts. 
The  bridge  seat  5  for  the  stringers  is  18  in.  deep.  The 
abutments  behind  the  bridge  seat  are  built  up  to  the  top  of 
the  embankment,  thus  keeping  the  earth  from  falling  down 
upon  the  bridge  seat.  The  spool  M  and  a  device  for  holding 
the  strut  O  in  position  are  shown  in  detail  at  T. 

In  ordinary  open  culvert  masonry  the  bridge  seat  and 
steps  are  the  only  dressed  stone  used  in  the  structure,  the 
body  of  the  walls  being  built  of  well-scabbled  rubble.  Large 
stones  with  good  beds  should  compose  the  bulk  of  the  walls, 
and  when  under-sized  stones  are  used  they  must  be 
thoroughly  bonded  by  large  ones.  The  wall  plates  should 
be  placed  as  nearly  over  the  center  of  the  wall  as  possible,  so 
that  the  shock  and  load  of  the  passing  train  may  be  equally 
distributed  throughout  the  abutments. 

1 467.  Arched  Culverts. — When  the  volume  of  water 
is  too  great  to  be  discharged  by  a  double-box  culvert  with 
openings  3  X  4  feet,  an  arcbed  culvert  is  substituted  with 
a  single  opening  of  the  required  area.  In  determining 
dimensions  of  culvert  openings,  the  greater  danger  lies  in 
making  them -too  small.  The  volume  of  surface  water 
discharged  from  a  given  area  depends  on  widely  differmg 
conditions,  and  is  often  in  apparent  violation  of  all  pre- 
scribed rules.  It  is  not  within  the  province  of  the  engineer 
to  attempt  to  meet  phenomenal  conditions,  but  he  should 
meet  common  extremes,  and  there  is  no  branch  in  railroad 


886 


RAILROAD   CONSTRUCTION. 


construction  where  he  so  often  blunders  as  in  the  matter  of 
culverts. 

1468.  Parts  of  an  Arch. — Fig.  387  represents  an 
arched  culvert  in  which  the  distance  D  £  is  called  the  span, 
O  F  the  rise,  the  lower  boundary  line  D  F  E  the  soffit 
or  intrados,  the  upper  boundary  G  B  H  the  back  or 
extrados.     The  end  of  the  arch  included  between  the  lines 


Fig.  387. 

D  F  E  and  G  B  H  is,  called  the  face.  Lines  level  with  D 
and  E  and  at  right  angles  to  the  face  of  the  arch  are  called 
springing  lines  or  springs.  The  blocks  of  which  the 
arch  is  composed  are  called  arcti  stones  or  voussoirs. 
The  center  one  B  F  is  the  keystone,  and  the  lowest  ones 
A  and  C  the  springers.  The  parts  B  G  and  B  H  are  the 
baunclies.  The  spaces  BGNK  and  B  H ML  are  the 
spandrels.  The  material  deposited  in  these  spaces  is 
the  spandrel  fllling.  It  is  sometimes  earth  and  sometimes 
masonry  or  partly  of  both. 

Arches  according  to  their  forms  have  different  names. 


RAILROAD   CONSTRUCTION.  887 

That  in  Fig.  387  is  a  semicircular  arch,  and  is  the  form 
commonly  adopted  in  culvert  building.  A  circular  arch 
containing  an  arc  of  less  than  180°  is  called  a  segmental 
arch  (see  Fig.  388).     The  arch  shown  in  Fig.  389,  composed 


Fig.  388.  Fig.  389. 

of  three  circular  arcs,  is  called  either  an  elliptical  or  a 
three-centered  arch. 

1469.     To  Find  the   Depth  of  Keystone. — For  cut 

stone  arches,  whether  circular  or  elliptic,  find  the  radius  O  D, 
Figs.  387,  388,  and  389,  which  will  touch  the  arch  at  Z>,  F, 
and^. 

Rule  I. — Add  together  this  radius  and  half  the  span  D  E. 
Take  the  square  root  of  the  sum.  Divide  this  square  root  by  Jf. 
and  add  to  the  quotient  -^  of  a  foot. 

Or,  by  formula, 

depth  of  keystone  in  feet  = 

{r^dt^i±M^j^,^foot.      (103.) 

For  second-class  work,  increase  this  depth  of  keystone  about 
I  part;  for  brickwork  or  fair  rubble,  about  \  part. 

Example. — The  radius  (9  D\%  18  feet,  the  span  Z>  .£"36  feet;  required, 
the  depth  of  an  arch  of  cut  stone  for  second-class  work  and  for  brick- 
work. 

Solution. — Applying  formula  103,  we  have 


4/18  +  18 
For  cut  stone,  depth  of  arch  = r +.2  foot  =  1.7  feet.     Ans. 


888  RAILROAD   CONSTRUCTION. 

For  second-class  work,  increase  depth  of  cut  stone  arch  |  =  1.7 + 
iX  1.7  =  1.91  feet.     Ans. 

For  brick  or  fair  rubble,  increase  depth  of  cut  stone  arch  ^  =  1.7  + 
iX  1.7  =  2.12  feet.     Ans. 

Rankine's  formula  for  depth  of  keystone  in  feet  is, 

dcptJi  of  keystone  in  feet  =  \^.1'Z  radius.  (104.) 

The  latter  formula  may  serve  where  all  conditions  are 
theoretically  perfect,  but,  under  ordinary  conditions,  the  re- 
sults given  by  this  formula  are  too  small.  The  arch  stones 
of  a  3G-foot  arch  should  be  at  least  1  ft.  9  in.  in  depth,  for 
considerations  of  appearance  as  well  as  security. 

To  find  the  radius  O  D,  Figs.  387,  388,  and  389,  whether 
the  arch  be  circular,  segmental,  or  elliptical: 

Rule  II. — Square  half  t/ie  span;  square  the  whole  rise ; 
add  these  squares  together  and  divide  the  sum  by  twice  the 
rise.      The  quotient  is  the  required  radius  O  D. 

Example. — The  span  is  30  feet;  the  rise  10  feet;  required,  the 
radius  O  D. 

-,                     „    ,.          15»  +  10'      325      ,«o..*     *      A 
Solution. — Radius  = -^ —  =  -^  =  16.25  feet.     Ans. 

1470.  To  Proportion  the  Abutments  for  a  Stone 
Arch,  whether  Circular  or  Blliptical : 

Rule. — Find  the  radius  O  D,  Fig.  387,  in  feet  which  will 
touch  the  arch  at  D,  F,  and  E.  Divide  this  radius  by  5.  To 
the  quotieyit,  add  -^^  of  the  rise  afid  2  feet.  The  sum  ivill  be 
the  thickness  D  N  or  E  M  of  each  abutment  at  the  springing 
line  for  any  abutment  whose  height  E  T  does  not  exceed  li^ 
times  its  base  T  U.  If  of  rough  rubble,  add  6  inches  to  E  M 
to  insure  full  thickness  in  every  part. 

Or  by  formula. 

Thickness  of  abut- 
ment at  spring  line  in 
feet,  when  the  height 
does  not  exceed  1\ 
times  the  base 


radius  in  feet  ,  rise  in  feet  ,  ^  ^    , 
^  ^^         (106.) 


Mark  the  points  M  and  A'^  thus  obtained.     Next,  from  the 


RAILROAD   CONSTRUCTION.  881) 

center  6>  of  the  span  or  chord  D  E,  lay  off  O  F(Fig.  387) 
equal  to  ^^  of  the  span,  and  join  F  and  V.  Through  the 
point  J/ draw  the  line  R  6^ parallel  to  F  V,  which  will  mark 
the  back  of  the  abutment  E  T  U  M.  In  the  same  way, 
draw  the  line  5  NX ,  marking  the  back  of  the  other  abutment. 
Now  on  the  lines  MR  and  A^ 5  mark  the  points  R  and  5,  their 
height  above  the  line  M  N  being  half  O  B,  the  full  height  of 
the  arch.  Produce  the  line  B  O,  and  upon  that  line  as  at  P 
locate  a  center  from  which  an  arc  may  be  described, 
passing  through  S,  B,  and  R.  This  arc  will  mark  the  top  of 
the  masonry  filling  above  the  arch,  except  when  the  rise  is 
about  \  of  the  span  or  less,  in  which  case  the  masonry  back- 
ing must  be  carried  up  solid  to  the  level  K  L  oi  the  top  of 
the  arch.  Ordinarily,  the  height  E  T  oi  the  abutment  will 
not  exceed  1^  times  the  base  T  U.  Incase  the  height  should 
exceed  E  T,  a.s  E  ]',  make  the  base  V  Z  equal  to  T  6^  in- 
creased by  \  the  additional  height  T  Y.  Then,  from  ^  draw 
a  line  parallel  to  U R,  which  will  mark  the  back  line  of  the 
abutment.  It  is  a  common  practice  to  give  to  the  faces  of 
the  abutment  a  batter  of  from  ^  inch  to  1  inch  to  the  foot, 
shown  in  the  dotted  line^  T'  V.  This  considerably  in- 
creases the  base  of  the  abutment,  and,  proportionately,  its 
stability.  An  arc  struck  from  the  center  P'  with  a  radius 
P'  R',  R'  being  level  with  R,  will  mark  the  top  of  the  masonry 
filling  above  the  arch. 

1471.  Foundations  for  Arch.  Culverts. — As  arch 
culverts  usually  require  a  greater  amount  of  masonry  than 
box  culverts,  their  foundation  must  be  proportionally 
stronger.  The  general  directions  given  for  box  culvert 
foundations  will  answer  for  arch  culverts  of  small  span,  say 
from  4  to  8  feet.  For  greater  spans,  unless  the  natural 
foundation  is  firm  and  secure,  such  as  hard  clay,  sand,  gravel, 
or  rock,  a  deep  trench  must  be  dug  to  receive  the  founda- 
tion. If  the  soil  is  soft  or  marshy,  it  may  be  necessary  to 
drive  piles  and  cut  them  off  at  a  uniform  elevation  below 
the  water-line,  and  fill  between  and  to  the  depth  of  one  foot 
above  tops  of  piles  with  concrete  made  with  hydraulic  cement. 


800 


RAILROAD   CONSTRUCTION. 


The  trench  should  extend  outside  the  lines  of  the  founda- 
tion at  least  12  inches,  in  order  that  the  pressure  of  the 
superstructure  may  be  sufficiently  distributed.  The  first 
course  of  masonry  should  project  at  least  0  inches  outside 
the  main  body  of  the  abutment  for  the  same  reason,  and 
should  be  composed  of  much  larger  stones  than  those  which 
form  the  main  body  of  the  superstructure.  The  paving  be- 
tween the  abutments  and  curbing  at  ends  of  arch  should  be 
of  the  same  dimensions  as  adopted  for  box  culverts.  A 
partial  section  of  arch  culvert  with  concrete  foundation  is 
shown  in  Fig.  390.     The  stones  forming  the  impost  course 


at  A,  in  a  culvert  of  16  feet  span,  should  be  from  0  inches  to 
12  inches  thick. 

1472.  Concrete. — The  concrete  for  the  foundations 
should  be  composed  of  the  following  ingredients:  Cement, 
1  part;  sand,  3  parts;  broken  stone,  5  parts.  If  the  con- 
crete is  to  be  deposited  below  the  water  level,  Portland 
cement  should  invariably  be  used.  If  the  pit  is  free  from 
water  at  the  time  of  construction,  though  ordinarily  below 
water  level,  Rosendale  or  any  other  good  American  cement 
may  be  used.  The  value  of  concrete  depends  much  upon 
the  quality  of  the  sand  and  broken  stone  used  and  the  man- 
ner of  mixing.     Sand  containing  loam  should  never  be  used, 


RAILROAD   CONSTRUCTION.  891 

and  if  none  other  is  available,  the  sand  should  be  washed  in 
a  slight  current  of  water,  which  will  remove  all  the  loam. 
The  stone  should  be  broken  to  a  fairly  uniform  size,  and  con- 
tain no  piece  which  will  not  pass  through  a  2^-inch  ring. 
If  suitable  stone  is  not  available,  hard-burned  brickbats, 
broken  to  the  requisite  size,  form  an  excellent  substitute. 
For  mixing  concrete  a  level  platform  of  rough  boards  is  pre- 
pared, convenient  to  the  foundation  pit.  A  suitable  quantity 
for  mixing  is  the  above  given  proportions  in  barrels  of 
material,  viz.,  1  barrel  of  cement,  2  barrels  of  sand,  and  5 
barrels  of  broken  stone.  The  broken  stone  is  deposited  in 
a  regular  pile,  12  inches  in  thickness.  Upon  the  same  plat- 
form the  sand  and  cement  are  mixed  in  a  dry  state,  after 
which  water  is  added  to  them  and  they  are  worked  into  a 
mortar  of  uniform  consistency.  The  mortar  is  then  spread 
evenly  over  the  stones,  and  the  whole  mixed  with  shovels, 
commencing  at  the  outside  of  the  pile  and  working  towards 
the  middle;  which  when  reached,  the  shovelers  reverse  the 
movement,  working  towards  the  outside  and  casting  the  con- 
crete towards  the  middle,  so  that  when  the  outside  of  the 
pile  is  reached,  the  whole  will  be  thoroughly  mixed.  It  is 
injurious  to  work  the  concrete  over  repeatedly.  Twice 
handling  with  the  shovel,  if  thoroughly  done,  is  sufficient. 
The  concrete  should  be  deposited  in  the  foundation  pit 
without  delay,  before  setting  commences;  and  with  quick 
setting  cements,  especially  in  summer  weather,  the  process 
is  rapid.  It  is  most  conveniently  handled  in  wheelbarrows, 
and  can  be  deposited  directly  from  them  into  the  pit.  In 
marshy  situations,  it  is  a  common  practice  to  confine  the 
concrete  by  inclosures  of  rough  boards  held  together  by 
stakes  driven  in  the  ground.  As  soon  as  the  concrete  is  de- 
posited from  the  barrow,  it  must  be  spread  with  hoes  or 
shovels  into  uniform  layers,  the  thickness  of  which  will  de- 
pend upon  the  depth  of  concrete  to  be  deposited.  If  only 
12  inches  of  concrete,  it  should  be  deposited  in  two  layers  of  6 
inches  each,  and  each  layer  well  rammed  as  soon  as  deposited. 
Rammers  of  about  35  pounds  weight,  similar  to  those  used 
in  street  paving,  are  recommended.     They  are  of  wood  4 


892  RAILROAD   CONSTRUCTION. 

feet  long,  G  to  8  inches  in  diameter  at  foot,  with  a  lifting 
handle.  Ramming,  when  properlj'  done,  consolidates  the 
mass  of  concrete  about  5  or  6  per  cent.,  rendering  it  less 
porous  and  increasing  its  strength.  Water  collecting  upon 
the  surface  of  the  concrete  gives  evidence  of  sufficient  ram- 
ming. The  surface  of  the  concrete  should  be  brought  to  a 
uniform  level,  and  sufficient  time  be  allowed  for  setting 
before  the  abutments  are  started. 

1473.  Mortar. — Cement  mortar  should  be  exclusively 
used  in  the  construction  of  arch  culverts,  the  cement  to  be 
well  tested  and  approved  before  being  allowed  to  go  into  the 
work.  Cement  which  does  not  show  a  tensile  strength  of 
40  pounds  to  the  square  inch  after  remaining  in  water  2-t 
hours  should  be  rejected.  The  common  American  cements, 
if  of  good  quality,  mixed  in  the  proportion  of  1  part  of  ce- 
ment to  2  parts  of  sand,  will  afford  a  mortar  suitable  for  any 
ordinary  engineering  structure.  Mortar  should  never  be 
mixed  in  large  quantities,  lest  its  strength  be  impaired  by 
setting  before  using.  The  proper  practice  is  to  mix  only 
such  quantities  as  can  be  used  immediately,  thus  keeping 
the  supply  perfectly  fresh  and  insuring  the  highest  results. 
The  cement  and  sand  should  always  be  mixed  dry,  the  water 
being  added  afterwards,  and  the  whole  thoroughly  worked 
with  a  hoe  before  using. 

The  use  of  cheap  brands  of  cement  is  false  economy. 
Ordinary  cement  will  admit  of  sand  in  the  proportion  of  tzuo 
parts  of  sand  to  one  of  cement.  The  best  Portland  cement, 
especially  for  work  not  requiring  rapid  setting  mortar,  will 
bear  four  parts  of  sand.  Hence,  the  latter  may  be  used 
with  the  same  economy  as  the  former,  even  at  twice  the  cost 
per  barrel. 

1474.  Pointing  of  Joints. — Arch  culverts  for  water- 
ways are  invariably  rubble  masonry,  but  of  the  best  of  its 
kind.  Sometimes  the  corner  stones  of  the  abutments,  as  well 
as  the  arch  stones  of  the  faces,  are  of  cut  stone.  The  joints 
of  these  should  be  left  open  at  the  faces  until  the  work  is 
well  advanced  or  completed,  when  they  should  be  pointed 


RAILROAD   CONSTRUCTION. 


893 


with  mortar  made  of  the  best  cement  in  the  proportions  of 
1  part  of  cement  to  1  part  of  sand,  and  neatly  dressed  with 
a  pointing  tool.  The  joints  of  the  rubble  masonry  are 
simply  struck,  i.  e.,  the  trowel  is  pressed  against  the  mortar 
and  drawn  the  full  length  of  the  joint,  forming  a  water- 
shed for  each  joint.  The  joints  are  struck  as  the  stones 
are  laid,  the  same  mortar  being  used  at  the  faces  as  in  the 
interior  of  the  walls. 

There  are  two  principal  methods  used  in  pointing  cut 
stone,  as  shown  in  Figs.  391  and  392.  Fig.  391  shows  the 
form  in  most  general  use.      It  is  not  so  ornamental  as  that 


Fig.  391.  Fig.  39~'. 

shown  in  Fig.  392,  but  it  is  less  exposed  to  the  weather,  and, 
hence,  is  more  enduring  and  a  more  certain  protection  to 
the  joints.  Mortar  intended  for  pointing  must  be  used 
immediately  after  mixing,  and  the  pointing  tool  repeatedly 
run  over  the  joint  or  bead,  under  considerable  pressure,  in 
order  to  compress  the  mortar  and  give  it  a  smooth  surface 
and  uniform  groove  or  projection. 

1 475.  Centers  for  Arches. — A  center  is  a  temporary 
wooden  structure  for  supporting  an  arch  while  it  is  being 
built.  Centers  are  built  lying  flat  on  a  fixed  platform,  to  a 
full-sized  drawing,  and  vary  widely  in  design,  according  to 
the  type  and  dimensions  of  the  arch.  The  different  parts  of 
a  center  are  given  in  Fig.  393,  which  is  a  standard  type  of 
centering  for  all  arches  of  moderate  span,  say  from  6  to  16  feet. 


894 


RAILROAD   CONSTRUCTION. 


The  frames  A,  A  are  made  of  ribs  of  1^-inch  plank  and 
united  as  shown  in  the  figure,  breaking  joints  and  fastened 
together  with  spikes.  The  ribs  are  fitted  to  the  drawing  as 
the  frames  are  built.  The  ribs  are  4  ft.  1  in.  in  length,  8  in. 
in  width  at  ends,  and  10  in.  in  width  at  middle,  the  edge 
being  trimmed  down  to  fit  the  curve  of  the  arch.  The  chord 
B  is  composed  of  two  planks,  each  \^  in.  thick  by  10  in.  in 
width  and  1(5  ft.  in  length,  spiked  securely  to  the  frames. 
The  upright  strut  C  is  3  in.  thick  by  10  in.  in  width,  placed 


'  1 

pr 

1 

\     I 

1 

1 

1 

I 

1 

1     I 

1 

Ij^ 

1     1 

jCD 

I 

directly  under  the  crown  of  the  arch  and  fastened  to  the 
frame  by  two  cleats  D  securely  spiked  to  both  frame  and 
strut.  Its  foot  passes  between  the  planks  forming  the  chord 
to  which  it  is  spiked.  The  brace  E  is  fastened  at  top  to  the 
strut  with  spikes.  Its  foot  passes  between  the  chord  planks 
and  is  shaped  to  abut  against  the  rib  at  the  spring  line, 
being  securely  spiked  to  the  chord.  The  frames  are  spaced 
3  feet  from  center  to  center,  and  rest  on  G  in.  by  G  in.  caps 
/  which  are  supported  by  6  in.  by  G  in.  posts  G.  These  posts 
rest  on  4  in.  by  G  in.  ground  sills  H  which  rest  on  the  stone 
paving.  On  the  caps  directly  under  each  frame  are  striking 
or  lowering  wedges  K,  by  means  of  which  the  frames  are 
raised  in  case  any  of  the  posts  should  settle. 


RAILROAD   CONSTRUCTION.  895 

1476.  Striking  Centers. — Upon  the  completion  of 
the  masonry,  the  lowering  wedges  are  removed,  which  per- 
mits of  the  removal  of  the  centering.  This  process  is  called 
striking  the  centers.  There  is  great  difference  of  opinion  as 
to  the  length  of  time  which  should  elapse  after  the  comple- 
tion of  the  masonry  before  the  centers  are  struck.  In  the 
case  of  brick  and  rubble  arches  where  the  mortar  forms  a 
considerable  part  of  the  mass,  a  period  of  two  or  three 
months  should  elapse  before  the  centers  are  struck.  This 
will  allow  the  mortar  to  harden  and  prevent  undue  com- 
pression of  the  joints  and  consequent  settlement  of  the  arch. 

1477.  General  Directions  for  the  Building  of  an 
Arch. — All  arch  stones  must  be  laid  with  beds  in  radial 
lines.  The  joints  at  the  intrados,  or  soffit,  will,  therefore, 
be  thinner  than  at  the  extrados,  or  back.  All  rough  pro- 
jections must  be  removed  from  the  beds  of  the  stones,  and 
the  stones  laid  in  firm  beds  with  broken  joints.  Until  the 
arch  is  half  built,  the  backing  need  not  be  started,  as  an  ex- 
cess of  weight  on  the  haunches  is  liable  to  cause  a  lifting  of 
the  crown.  In  arches  of  large  span  it  is  a  common  practice 
to  load  the  centering  at  the  crown  until  45°  of  the  arch 
above  the  springing  line  is  completed.  When  the  45°  line  is 
passed  and  the  pressure  on  the  centering  becomes  more 
nearly  vertical,  the  backing  must  be  carried  up  to  take  the 
pressure.  The  continuance  of  the  centering  will  be  no 
hindrance  to  traffic  over  the  bridge. 

1478.  Wing  Walls. — Wing  walls  are  generally  built 
with  faces  diverging  at  an  angle  of  130°  from  the  face  of  the 
arch.  Their  foundations  are  prepared  at  the  same  time  as 
the  abutment  foundations,  and  varied  to  suit  the  different 
heights  of  wall  above  them.  Abutments  and  wing  walls  are 
carried  up  together,  the  stones  of  both  walls  interbonding  so 
as  to  form  one  solid  mass  of  masonry.  The  thickness  of  the 
wing  walls  at  foundation  line  should  ordinarily  be  y*g-  of  the 
full  height  of  the  wall  at  that  point,  with  faces  battered  from 
1  to  1^  inches  to  the  foot  and  having  a  thickness  of  2^  feet 
at  the  top. 


896  RAILROAD   CONSTRUCTION. 

When  y\  of  the  height  of  the  wall  (allowing  a  batter  of 
1  inch  to  the  foot)  does  not  give  a  thickness  of  2^  feet  at 
the  top,  the  thickness  of  foundation  must  be  sufficiently  in- 
creased to  insure  that  thickness  at  the  top.  Where  wing 
walls  attain  a  height  of  12  feet  and  over,  make  the  thickness 
of  the  foundation  ^  of  the  height.  Sometimes  the  slope  of 
the  back  of  the  wall  is  broken  up  into  steps  instead  of  being 
uniform.  Some  advantage  is  gained  from  such  treatment, 
as  the  weight  of  the  back  filling  bears  directly  upon  the  pro- 
jecting stones.  Any  attempt  to  give  the  back  a  smooth, 
uniform  slope  should  be  avoided.  It  adds  nothing  to  the 
appearance  of  the  work,  as  it  is  covered  by  the  embankment, 
and  lessens  the  friction  of  the  filling  against  the  back  of  the 
wall,  which  tends  to  prevent  its  overturning.  It  is  far 
better  to  increase,  the  size  of  the  stones,  allowing  their  rough 
edges  to  project  from  the  rear  face.  The  large  stones  act 
as  binders  for  the  smaller  ones,  greatly  increasing  the  sta- 
bility of  the  wall,  and  the  projections  afford  the  necessary 
friction  to  the  filling.  A  general  plan  of  a  semicircular  arch 
culvert,  including  parapet  and  wing  walls,  is  given  in 
Fig.  394. 

The  span  A  B  is  m  feet,  and  the  rise  CD  8  feet.     The 

thickness  of  arch  D  £  is  found  by  applying  formula  103, 

Art.  1469, 

»      /     /-  F                •     /-           i^ radius  4-  half  span   ,     ^  ^    , 
aeptli  of  keystone  tn  feet  = -^—^ (-  .  2. foot. 


^   ^     .       .         .         ^.  .  ,          4/8  feet  -4-  8  feet 

Substitutmg  given  dimensions,  we  have  — 


4 

.2  foot  =  1.2  feet,  which  is  the  depth  of  key  given  for  cut 

stone.      As  the  rule  calls  for  \  greater  depth  for  arches 

of  rubble,  which  is  the  material  supposed  to  be  used  in  the 

1  2  feet 

arch  under  consideration,  — ^ — =  .3  foot;  1.2  +  .3  =  1.5 

4 

feet  =  required  depth  of  keystone.     The  length  of  the  soffit 

A  D F  is  equal  to  half  the  circumference  of  a  circle  whose 

diameter  is   10  feet.      Its  length   is,   therefore,    25.13   feet. 

The  number  of  stones  in  an  arch  should  always  be  an  odd 

number,  which  will  place  the  keystone  in  the  center  of  the 


RAILROAD   CONSTRUCTION. 


897 


arch  and  give  an  equal  number  of  arch  stones  on  both  sides 
of  the  key.  If  now  we  make  the  thickness  of  the  arch 
stones  12  inches  from  center  to  center  of  joint  on  the  soffit, 
the  arch  will  contain  13  such  stones  on  each  side  of  the  key 
and  leave  13|-  inches  for  the  thickness  of  the  keystone. 
The  height  of  the  abutments  F F'  we  take  at  6  feet.     The 


thickness  F  G  oi  the  abutments  at  spring  line  we  find  by 
applying  formula  105,  Art.  1470. 

Thickness  of  abut- " 
mcnt  at  spring  line  in 
feet,  when  height  of 
abutment  does  not  ex- 
ceed 1^  times  its  base 

Substituting  given  dimensions,  we  have  thickness  of  abut- 

8         8 
jnent  at  spring  line  in  feet  =  —  -f-  —  -|-  2  ft.  =4.4  feet. 


radius  in  feet  .  rise  in  feet  ,  „    ,.    ^ 

= 5-^+ j/-+2A^'. 


898 


RAILROAD   CONSTRUCTION. 


This  thickness  of  abutment  is  for  first-class  masonry.  As 
our  structure  is  of  rubble,  we  add  ^  foot  to  4.4  feet,  which 
gives  4.9  feet..  We  further  increase  the  thickness  of  the  abut- 
ments to  5.0  feet,  which  will  insure  perfect  stability  without 
any  excess  of  masonry.  We  give  to  the  back  of  the  abut- 
ment wall  a  batter  of  1  inch  to  the  foot,  making  the  thick- 
ness of  the  abutments  at  the  ground  line  X  Y  5  feet  6 
inches.  The  height  of  the  points  L  and  J/ above  the  spring 
line  is  4  feet  and  9  inches,  equal  to  one-half  the  full  height 
C  £  of  the  arch.  The  arc  L  E  M  which  limits  the  top  of 
the  backing  or  spandrel  filling  is  struck  with  the  radius 
W L^  18  feet  9  inches  in  length,  found  by  trial.  The  wing 
walls  O  and  Pare  shown  in  plan  at  Q  and  R.  A  section  of 
wing  wall  at  5"  7"  is  shown  in  full  at  U.  The  top  N  of  the 
parapet  is  1  foot  9  inches  above  top  of  arch.  The  parapet 
and  wing  walls  have  a  coping  of  dressed  stone  6  in.  in 
thickness. 


1479.  General  Directions  for  Building  Rubble 
Walls. — Small  stones,  excepting  for  back  filling,  should  not 
be  used,  provided  those  of  suitable  size  can  be  had  at 
reasonable   cost.       Stones   of   too   great    size    are    equally 

objectionable  unless  they  have 
full  beds  and  reach  from  face  to 
face  of  wall.  Many  rubble  walls 
are  built,  as  shown  in  Fig.  395, 
of  large  stones  showing  on  one 
face,  but  extending  only  a  short 
distance  into  the  wall,  while  the 
back  and  body  of  the  wall  are 
composed  of  small  stones.  The 
back  of  the  wall,  having  so  much 
greater  proportionof  mortar  than 
the  front,  will  in  high  walls  settle 
considerably  more  than  the  front,  producing  cracks  in  the 
masonry.  The  almost  total  lack  of  binders  is  an  even 
greater  source  of  weakness.  Such  a  wall  is  objectionable  in 
any  situation,  but  when  serving  as  a  retaining  wall  for  a 


Fig.  395. 


Fig.  396. 


RAILROAD   CONSTRUCTION. 


899 


railroad  embankment  where  the  back  filling  is  subjected  to 
the  constant  vibrations  caused  by  passing  trains,  its  ultimate 
failure  is  almost  certain. 

A  full  proportion  of  large  stones  should  show  on  both 
front  and  back  and  extend  well  into  the  wall,  binding  the 
wall  compactly  together,  as  shown  in  Fig.  396. 


RETAINING  WALLS. 

1480.  A  retaining  wall  is  one  for  sustaining  the 
pressure  of  earth,  sand,  rock,  or  any  other  substance 
deposited  behind  it  after  it  is  built.  The  material  deposited 
is  called  filling  or  backing.  Retaining  walls  are  much 
used  in  railroad  construction,  especially  in  sections  where 
the  natural  slope  of  the  ground  approaches  closely  to  that 


Fig.  397. 

of  the  angle  of  ordinary  earth  filling,  viz.,  1^  horizontal  to 
1  vertical.  Railway  tracks  entering  towns,  especially  where 
they  cross  or  crowd  other  lines,  terminal  grounds,  etc., 
invariably  require  retaining  walls.  The  pressure  exerted 
by  the  backing  will  vary  greatly,  depending  upon  the  slope 
of  the  ground  behind  the  wall,  the  nature  of  the  material 
composing  the  backing,  and  the  manner  of  depositing  it;  but 
chiefly  depending  upon  the  height  of  the  backing.  The 
usual  form  of  retaining  wall  is  shown  in  Fig.  397.     There  is 


900 


RAILROAD   CONSTRUCTION. 


no  invariable  rule  for  determining  the  dimensions  of  retain- 
ing walls,  and  the  rules  of  various  authors  differ  widely. 
The  following  rule  by  Trautwine  is  based  upon  careful 
experiments  and  is  widely  adopted.  The  back  of  the 
wall  is  vertical,  and  the  foundations  not  more  than  3  ft. 
deep. 

Rule.  —  1 V lie 71  the  backing  is  deposited  loosely,  being  du  mped 
from  earts,  barrows,  etc.,  zuall  of  cut  stone  or  first-class  large 
ranged  nibble  in  mortar,  base  C  D  equals  .35  of  the  vertical 
height  D  B;  wall  of  good  common  scabbled  mortar  rubble,  or 
brick,  base  C  D  equals  .Jf.  of  the  vertical  height  D  B;  wall  of 
well-scabbled  dry  rubble,  base  C  D  equals  .5  of  the  vertical 
height  D  B. 

When  the  backing  is  deposited  in  layers  and  well  rammed, 
these  dimensions  may  be  somewhat  reduced,  but  there  is  no 
fixed  rule.  In  general,  the  additional  cost  of  spreading  and 
ramming  will  quite  equal  the  saving  in  masonry. 

In  Fig.  397,  the  height  B  B  is  6  feet.  The  wall,  supposed 
to  be  of  dry  rubble,  has  a  base  of  3  feet  4  inches.  The 
foundation  is  laid  in  a  trench  about  1  foot  in  depth,  with  a 
footing  or  offset  F  G  6  inches  in  width.  The  face  is 
battered  1  inch  to  the  foot,  which  gives  the  wall  a  more  sub- 
stantial appearance,  though  clearly  adding  nothing  to  its 
stability. 

Earth    and    sand    are    the    materials  commonly   used  for 
backing.    When  broken  stone, 
gravel,  boulders,  or   clay  are 
to  be  used,  additional  weight 
must  be  given  to  the  wall. 

By  inclining  the  base  A  B 
of  the  wall  (see  Fig.  398),  the 
friction  of  the  wall  against  the 
foundation  is  increased  and 
the  danger  of  overturning 
lessened.  As  was  stated  in 
Art.  1478,  the  rough  bat- 
tered   back   of   the  wall  also  *''0'  896. 


RAILROAD   CONSTRUCTION. 


901 


increases  the  friction  of  the  backing,  tending  to  prevent 
overturning.  The  batter  of  the  face  should  not  exceed  1^ 
inches  to  the  foot.  Any  increase  is  liable  to  catch  water 
running  down  the  face  and  carry  it  into  the  wall.  This 
danger  is  increased  where  the  joints  of  the  masonry  are  in- 
clined backwards,  as  in  Fig.  308.  To  obviate  this  danger, 
the  face  stones  are  sometimes  laid  in  mortar. 

1 481 .  Guarding  Against  Frost. — Where  deep  freez- 
ing occurs,  the  back  of  the  wall  should  be  sloped 
forwards,  as  shown  in  Fig.  399  at  ad,  and  smoothly 
finished  to  lessen  the  hold  of  the  frost,  which 
might  otherwise  displace  the  masonry.  The  foot 
of  the  slope  d  should  be  at  the  frost  line,  usually 
three  or  four  feet  below  the  surface  a. 

1482.  Bulging. — Where  walls  are  too  thin,       Fig.399. 
they  usually  first  manifest   their  weakness  by  bulging  out- 
wards at  about  one-third  of  their  height  above  the  ground, 
as  at  a,  Fig.  400.     This   effect   is   sometimes  owing  to  the 

yielding  of  fresh  mortar, 
and  if  not  more  than  \  inch 
for  each  foot  in  thickness 
of  wall  at  a,  it  need  not 
cause  apprehension. 

Sometimes  retaining  walls 
fail  on  account  of  the  com- 
pression of  the  backing, 
causing  settlement  and  in- 
creased pressure  against  the 
wall.  This  is  especially  fre- 
quent where  the  backing 
supports  railway  tracks  car- 
rying heavy  and  rapidly 
moving  trains.  In  design- 
ing walls  for  such  situa- 
tions, this  heavy  additional 

weight  must  be  provided  for  by  additional  weight  in  the 

wall. 


Fig.  400. 


902 


RAILROAD   CONSTRUCTION. 


1483.  Offsetted  Back. — Having  proportioned  a  re- 
taining wall  abdc  in  Fig.  401,  by  the  foregoing  rule,  we 
can,  by  offsetting  the  back,  as  shown 
in  the  figure,  considerably  increase  its 
stability  without  adding  to  the  volume 
of  the  masonry. 

The  offsets  are  determined  as  fol- 
lows: Through  ^',  the  middle  point  of 
the  back,  draw  any  line  f  g.  From 
/"erect  the  perpendicular ///.  Divide 
g  Ji  into  any  even  number  of  parts,  in 
this  instance  4,  and  draw  through 
these  points  of  division  lines  parallel 
to/"  //.  Then  divide///  into  1  great- 
er number  of  equal  parts  than  gJi,  and  through  these  points 
of  division  draw  lines  at  right  angles  to  f  h,  forming  the 
offsets  as  shown  in  the  figure.     By  increasing  the  thickness 


Fig.  401. 


Fig.  402. 


Fig.  403. 


of  the  wall  at  the  base,  the  center  of  gravity  is  lowered  and 
the  stability  consequently  increased.  The  backing  included 
by  the  lines  ^/z  and  /// exerts  only  vertical  pressure  against 
the  offsets,  which  tends  greatly  to  prevent  the  overturning 
of  the  wall. 


RAILROAD   CONSTRUCTION. 


903 


1484.  Surcharged  Walls. — When  the  backing  is 
higher  than  the  top  of  the  wall  and  slopes  upwards  from  its 
inner  edge  a,  at  the  natural  slope  a  b  oi  1^  to  1  (see  Fig. 
402),  the  dimensions  given  in  Art.  1480  will  be  inadequate 
for  the  increased  pressure.  The  following  table  prepared 
by  Trautwine  gives  dimensions  of  walls  for  all  probable 
heights  of  backing: 

TABLE  29. 


^  a 
^•g- 

4> 
C 

o 

u  3. 

c 
o 

•o" 

8i> 

33     ^     en 

'^  J5 

t^m 

0;0 

"JB 

t:  m 

O  J2 

J3 

O    S    03 

n  o 

S   o 

3 

®    l3    rt 

OO 

^   o 

3 

Total   Height 
ing  as  Comp 
Height  of  W 

ffi    tn  x: 

If  a 

T3    9i 

Thick 
Pari 

ness  of  \ 
.8  of  Hei 

Vail  in 
ght. 

Thickness  of  Wall  in 
Parts  of  Height. 

1.0 

.35 

.40 

.50 

2.0 

.58 

.63 

.73 

1.1 

.42 

.47 

.57 

2.5 

.60 

.65 

.75 

1.2 

.46 

.51 

.61 

3.0 

.62 

.67 

.77 

1.3 

.49 

.54 

.64 

4.0 

.63 

.68 

.78 

1.4 

.51 

.56 

.66 

6.0 

.64 

.69 

.79 

1.5 

.52 

.57 

.67 

9.0 

.65 

.70 

.80 

1.6 

.54 

.59 

.69 

14.0 

.66 

.71 

.81 

1.7 

.55 

.60 

.70 

25.0 

1.8 

.56 

.61 

.71 

or  more 

.68 

.73 

.83 

When  the  slope  a  b  oi  the  backing  starts  at  the  front  a 
of  the  top  of  the  wall  (see  Fig.  403),  additional  thickness  is 
required.  The  triangle  a  c  d  showing  section  of  earth 
above  top  of  wall  exerts  only  vertical  pressure  against  the 
top  of  wall,  and,  hence,  increases  its  stability.  When  the 
backing  reaches  above  the  top  of  the  wall,  as  in  Figs.  402 
and  403,  the  wall  is  surcharged.  The  following  table  by 
Poncelet  gives  thickness  of  walls  surcharged  with  dry  sand 
from  the  outer  edge  a,  Fig.  403: 


904 


RAILROAD   CONSTRUCTION. 


TABLE    30. 


i§^ 

c 
o 

0) 

c 
o 

*^  ll 

kl 

m   & 

■^  c 

u 

^1 

a  1- 

03    "^    tn 

3     t 

o  h  «? 

iJl 

o   ^ 

°    rt    « 

"^  i 

bo  o    o 

^  c 

- 

J=  6  L^ 

bo  o    o 

.2   c 

*S  O  *i 

rt 
^ 

'v  o  z. 

03 

3^ffi 

Thickness 

of  Wall  in 

Thickness 

of  Wall  in 

o  - 

Parts  of 

Height. 

Parts  of 

Height. 

1.0 

.350 

.452 

2.0 

.707 

.930 

1.1 

.393 

.498 

2.4 

.762 

1.020 

1.2 

.439 

.548 

3.0 

.811 

1.110 

1.3 

.485 

.604 

4.0 

.852 

1.180 

1.4 

.533 

.665 

6.0 

.883 

1.250 

1.5 

.579 

.726 

11.0 

.909 

1.280 

1.6 

.617 

.778 

21.0 

.922 

1.310 

1.7 

.645 

.824 

31.0 

.926 

1.320 

1.8 

.668 

.847 

Infinite 

.934 

1.340 

1.9 

.690 

.903 

The  table  is  applied  as  follows  :  If  the  height  of  the 
backing  is  20  feet  and  the  retaining  wall  10  feet,  the  tabular 
height  of  backing  is  given  as  2,  and  the  thickness  of  the  re- 
taining wall,  if  of  cut  stone,  should  be  10  X  .707  =  7.07  feet. 

1485.  To  Prevent  Sliding.  —  ^  retaining  ivall  may 
slide  from  its  foundation  ivithout  losing  its  vertical  position. 
Where  the  wall  is  built  on  a  timber  platform  or  a  smooth 
rock  surface,  the  danger  of  sliding  is  great,  owing  to  insuf- 
ficient friction  between  the  wall  and  foundation.  To  pre- 
vent this,  strong  projecting  beams  are  built  into  a  timber 
platform  running  at  right  angles  to  the  direction  in  which 
the  wall  would  slide,  as  shown  in  Fig.  404.  On  wet  clay  the 
friction  is  about  ^  the  weight  of  the  wall ;  on  dry  earth,  from 
\  to  I,  and  on  sand  or  gravel,  from  f  to  f  the  weight  of  the 
wall. 


RAILROAD   CONSTRUCTION. 


905 


The  friction  of  masonry  on  a  timber  platform  is  about  ^jj 
of  its  weight  if  dry  and  f-  of  its  weight  if  wet,  i.  e.,  a  retain- 


ing wall   under    the  above  given   conditions  will  not  slide 
under  a  pressure  of  ^,  f,  f,  etc.,  of  its  total  weight. 

1486.     On  the  Theory  of  Retaining  ^Valls.  — Let 

a  bdc.  Fig.  405,  be  a  retaining  wall  with  battered  face  and 
vertical  back.  The 
top  b  e  oi  the  back- 
ing is  level  with  the 
top  of  the  wall. 
Let  d  e  represent 
the  natural  slope  of 
the  material  com- 
posing   the    filling,     — « g ^ 

viz  ,    1^    horizontal  fig.  405. 

to  1  vertical,  which  is  the  average  of  materials  used  for  back 

filling. 

It  is  assumed  that  the  wall  a  b  d  c\s  heavy  enough  to  re- 
sist sliding  along  its  base,  and  that  it  can  fail  only  by  over- 
turning, i.  e.,  rotating  about  its  toe  c.     Now,  if  the  angle 


906  RAILROAD   CONSTRUCTION. 

ode  between  the  vertical  line  o  </ drawn  from  the  inner  bot- 
tom edge  of  the  wall  and  the  natural  slope  d  c  be  divided  by 
the  line  d  f  \w\.o  two  equal  angles  o  d /  and  /  d  c,  thQ  angle 
o  ^/y  is  called  the  angle  and  the  line  d/the  slope  of  maxi- 
mum pressure.  The  triangular  prism  of  earth  o  d  f\s  called 
the  prism  of  maximum  pressure  because,  if  considered  as  a 
wedge  acting  against  the  back  of  the  wall,  it  would  exert  a 
greater  pressure  against  it  than  would  the  entire  triangle 
0  d  e  oi  earth  considered  as  a  single  wedge.  For  though  the 
last  is  more  than  double  the  weight  of  the  former,  yet  it  re- 
ceives much  greater  support  from  the  underlying  earth.  It 
has  been  proved  by  experiment  that  if  the  triangle  of  earth 
0  d  e  be  divided  by  any  line  df  into  wedges,  the  wedge  that 
will  press  most  against  the  wall  is  that  formed  when  the  line 
^/divides  the  angle  ode  into  two  equal  parts. 

The  angle  o  d  /i  formed  by  the  vertical  o  d  and  the  hori- 
zontal ^f// is  00°.  The  angle  of  natural  slope  /i  d  e  is  33° 
41';  hence,  the  angle  o  d  f  oi  maximum  pressure  is  equal  to 
90°  -  33°  41'  -^  2  =  28°  09'. 

In  making  calculations,  only  07ie  foot  of  the  length  of  ivall 
and  of  the  backing  is  taken,  so  that  all  that  is  necessary  is  to 
take  the  area  of  the  section  of  the  wall  and  backing.  The 
material  composing  the  backing  is  supposed  to  be  perfectly 
dry  and  possessing  no  cohesive  power,  which  is  practically 
true  of  pure  sand. 

If  we  conceive  the  wall  a  b  d  e.  Fig.  405,  to  be  suddenly 
removed,  the  triangle  b  d  f  oi  sand  included  between  the 
line  of  maximum  pressure  df  and  the  vertical  back  b  d  oi  the 
wall  would  slide  downwards  impelled  by  a  force  ;/  P,  acting 
in  a  direction  n  Pat  right  angles  to  the  side  b  d oi  the  tri- 
angle, i.  e.,  at  right  angles  to  the  vertical  back  b  d  oi  the 
wall,  its  center  of  force  being  at  /-*  distant  ^  way  between  b 
and  d,  measured  from  the  bottom  of  the  wall  d.  The  amount 
of  this  force  is  expressed  by  the  following  formula: 

Perpendicular  _  zveight  of  triangle  cf  earth  bdfx  of    . 
pressure  n  P  ~  vertical  depth  od  '   ^  '' 

This  formula  not  only  applies  to  walls  with  vertical  backs, 


Fig.  406. 


RAILROAD   CONSTRUCTION.  907 

as  in  Fig.  405,  but  to  those  with  inclined  backs,  as  in  Fig. 
406,  for  inclinations  as  high  as  6  inches  horizontal  to  1  foot 
vertical,  which  is  rarely  met  with  and  never  exceeded. 

1487.  Friction  Caused  by  Pressure  of  Back- 
ing.— If  all  the  backing  material  contained  between  the 
line  of  natural  slope  and 
the  back  of  the  wall  were 
unconfined,  it  would  slide, 
producing  motion,  but 
confined  by  the  retaining 
wall,  the  force  is  converted 
into  pressure  of  earth 
against  the  back  of  the 
wall,  resisted  by  \.\\^  fric- 
tion  between   the   compressed   earth   and  the   wall. 

If  the  wall  were  to  begin  to  overturn  about  its  toe  c 
(Figs.  405  and  406)  as  a  fulcrum,  its  back  b  d  would  rise, 
producing  friction  against  the  backing.  So  long  as  the  wall 
does  not  move,  the  friction  of  the  backing  acts  constantly, 
and  must,  therefore,  be  one  of  the  forces  which  prevent 
overturning.  We  ascertain  the  amount  and  effect  of  this 
friction  as  follows:  Let  a  bdc,  Fig.  407,  be  a  retaining 
wall,  and  let  n  P  represent  to  some  scale  the  perpendicular 
pressure  against  the  back  of  the  wall  calculated  by  formula 
106, 

perpendicular  _  iveiglit  of  triangle  b  df  x  of 
pressure  n  P  ~  vertical  depth  o  d 

Make  the  angle  n  P  h  equal  to  the  angle  of  wall  friction, 
viz.,  that  at  which  a  plane  of  masonry  must  be  inclined  in 
order  that  dry  sand  and  earth  may  slide  freely  over  it,  and 
taken  at  33°  41'  with  the  horizontal.  Draw  ;/  //  perpendicu- 
lar to  n  P  and  complete  the  parallelogram  //  h  k  P.  Then, 
k  /'will  represent  to  the  same  scale  the  amount  of  friction 
against  the  back  of  the  wall.  As  the  friction  acts  in  the  di- 
rection of  the  back  ^  ^  of  the  wall,  it  may  be  considered  as  act- 
ing at  any  point  Poi  the  line  of  the  back,  and  we  will  have  two 
forces,  viz.,  the  perpendicular  pressure  n  /*and  the  friction 


908 


RAILROAD   CONSTRUCTION. 


k  P  acting  at  P.  By  composition  and  resolution  of  forces, 
the  diagonal  h  P  measured  to  the  same  scale  will  give  us  the 
amount  of  their  resultant,  which  is  approximately  the  single 

a  X  b      o e  tlicorctical 

force   both    in 
amount  and  di- 
rection    which 
the  wall  has  to 
resist.         This 
force    includes 
the    wall    fric- 
tion. The  force 
Ji   P  is  always  equal  to  the    perpendicular 
force   n   P  divided   by   the   cosine  of   the 
angle  of  wall  friction.     The   cosine  of  the 
angle  of  wall  friction  is  .832,  and  the  value 
of  the  force  h  P  mzy  be  expressed  in  the 
following  formula  : 

Approximate  theoretical  pressure  h  P= 
iveight  of  triangle  bdfxof 
vertical  height  od  X  .^'i'l    '  ' 

When  the  back  of  the  wall  does  not  incline  forwards  more 
than  (j  inches  horizontal  to  1  foot  vertical,  equal  to  an  angle 
of  about  26°  34',  the  following  formula  by  Trautwine  is 
used,  viz. : 

Approximate  theoretical  pressure  Ji  P=. 
weight  of  triangle  bdfx.  G43,  ( 1 08.) 

which  includes  friction  of  earth  against  the  back  of  the  wall. 
When  the  back  of  the  wall  is  offsetted,  as  in  Fig.  401,  the 
direction  of  the  pressure  of  the  earth  will  be  the  same  as 
though  the  wall  had  the  batter/^. 

1488.  To  Find  the  Overturning  and  Resisting 
Forces. —  To  find  the  overturning  tendency  of  the  earth  pres- 
sure and  the  resistance  of  the  wall  against  being  overturned 
about  its  toe  c,  as  a  fulcrum,  see  Pig.  407.  Find  the  center 
of  gravity  g  of  the  wall,  and  through  g  draw  the  vertical 


RAILROAD   CONSTRUCTION.  909 

line  g  i.  Produce  the  line  of  pressure  Ji  P,  and  draw  c  v  at 
right  angles  to  this  line.  To  any  convenient  scale,  lay  off 
/  /  equal  to  the  weight  of  the  wall  and  to  the  same  scale  /  ;// 
equal  to  the  pressure  //  P.  Complete  the  parallelogram 
/  ;//  s  t.  The  diagonal  /  j  will  be  the  resultant  of  the  pres- 
sure and  the  weight  of  the  wall.  The  stability  of  the  wall 
will  be  the  greater  as  the  distance  c  r,  from  the  toe  to  the 
point  where  the  resultant  /  s  cuts  the  base,  increases.  To 
insure  stability,  c  r  must  be  greater  than  \  c  d. 

The  pressure  h  P,  if  multiplied  by  its  leverage  c  v,  will 
give  the  moment  of  the  pressure  about  c,  and  the  weight  of 
the  wall  //  multiplied  by  its  leverage  c  r' will  give  the 
moment  of  the  wall.  The  wall  is  secure  against  overturn- 
ing in  proportion  as  its  moment  exceeds  that  of  the  pressure. 

For  example,  let  the  height  of  the  wall^;^  d  c,  in  Fig.  407, 
be  9  ft. ;  the  thickness  at  the  base  c  d,  4.5  ft.,  and  at  the 
top  a  b^l  ft.,  and  the  batter  oi  a  c  be  1  in.  to  the  ft.  The 
triangle  of  earth  b  d f  has  a  base  b  f  ^^  6.57  ft.  and  altitude 
d  0  =■  S^  it.  Taking  the  section  as  1  foot  in  thickness,  Art. 
1486,  we  have  the  contents  equal  to  6.57  X  9  -^  2  =  29.56 
cu.  ft.  Assuming  the  material  to  weigh  120  lb.  per  cu.  ft., 
the  weight  of  the  triangle  b  df  is  29.50  X  120  =  3,547  lb., 
^/=  4.81  ft.  3,547x4.81  =  17,001.  17,001^^^^=1,895.7 
lb.  =  the  perpendicular  pressure  n  P.  Lay  off  on  a  line  per- 
pendicular to  the  back  of  the  wall  at  P,  to  a  scale  of  2,000  lb. 
=  1  in.,  71  P—  1,895.7  h-  2,000  =  .948  in.,  the  perpendicular 
pressure.  Draw  P  h,  making  the  angle  «  P  h=z  33°  41'. 
Draw  n  h  intersecting  h  P  in  //  ;  then  will  n  h  to  the  same 
scale  equal  the  friction  of  the  earth  against  the  back  of  the 
wall.  Completing  this  parallelogram,  n  h  k  P,  the  diagonal 
h  P=  1.139  in.,  which,  to  a  scale  of  2,000  lb.  to  the  inch, 
amounts  to  2,278  lb.,  and  is  the  resultant  of  the  pressure 
and  the  friction. 

Produce  the  resultant  h  P  to  u.  We  next  find  the  center 
of  gravity^  of  the  wall  a  b  d  c.  The  section  of  the  wall  is 
a  trapezoid,  and  the  center  of  gravity  g  is  readily  found  as 
follows:  Produce  the  upper  base  of  the  section  to  x,  making 
a  X  =1  c  d  ^=  4.5  feet.      Produce  the  lower  base  in  the  opposite 


910 


RAILROAD   CONSTRUCTION. 


direction  toj,  making ^j  =  a d  =  2  it.  Joiner  andj.  Find 
the  middle  points  x'  and  /'  of  the  upper  and  lower  bases  of 
the  section.  Join  these  points.  The  intersection  ^  of  the 
lines  X  y  and  x'  y'  is  the  center  of  gravity  of  the  trapezoid 
a  b  d  c. 

The  volume  of  the  section  of  wall  a  b  d  c  \%  readily  found. 
The  sum  of  top  and  bottom  widths  =  2.0  +  4.5  =  6.5  ft. 
6.5^2  =  3.25  ft.  3.25  X  9  =  29.25  cu.  ft.  29.25x154  = 
4,504  lb.  (the  weight  per  cubic  foot  of  good  mortar  rubble 


Fig.  408. 


=  154  lb.)  =  the  weight  of  the  section  a  b  d  c.  Draw 
through  g  a  vertical  line  g  /,  and  lay  off  in  it  to  a  scale  of 
2,000  lb.  to  the  inch  from  the  point  /,  where  the  line  of 
gravity  intersects  the  prolongation  of  the  line  of  pressure 
//  P^  the  length  /  /  equal  to  4,504  lb.,  the  weight  of  the  wall. 
Lay  off  from  /  on  the  prolongation  of  //  /*,  /  in  equal  to 
2,278  lb.  to  the  same  scale.  Complete  the  parallelogram 
/  VI  s  t.  The  diagonal  /  s  represents  the  resultant  of  the 
pressure  and  of  the  weight  of  the  wall.  The  distance  c  r 
from  the  toe  c  to  the  intersection  of  the  resultant  /  s  with 
the  base  ^  ^  is  more  than  \  of  the  width  of  the  base,  which 
insures  ample  stability. 


RAILROAD   CONSTRUCTION.  911 

1489.  Pressure  of  the  Backing  on  Surcharged 
Walls. — In  Fig.  408,  the  surcharge  of  backing  m  b  o  slopes 
from  b  at  its  natural  slope  and  attains  its  maximum  pressure 
where  the  slope  of  maximum  pressure  d  k  intersects  the 
natural  slope  b  in  at/.  Any  additional  height  of  surcharge 
does  not  increase  this  pressure.  If  the  surcharge  slopes 
from  a,  as  shown  by  the  line  a  p,  or  from  any  point  between 
a  and  b,  then  the  slope  of  maximum  pressure  must  be  ex- 
tended intersecting  the  slope  from  a  in  the  point  k.  The 
prism  of  maximum  pressure  will  then  be  d  i  k.  The  triangle 
of  earth  a  b  i  on  the  top  of  the  wall  exerts  no  pressure 
against  the  back  of  the  wall,  but  adds  to  its  stability. 

Having  found  the  weight  of  the  triangle  b  d  f,  we  have,  by 
formula  108,  Art.  1487, 

approximate  pressure  =  weight  of  triangle  b  d  f  x  .643, 

which  includes  the  pressure  of  the  backing  and  the  friction 
of  the  earth  against  the  back  of  the  wall. 

Draw  P  n  perpendicular  to  the  back  of  the  wall  and  draw 
h  P,  making  the  angle  n  P  h  —  33°  41',  the  angle  of  wall  fric- 
tion. Then,  h  P  will  be  the  direction  of  the  pressure.  The 
point  of  application  of  this  pressure  will  not  always  be  at  /*, 
\  of  the  height  oi  b  d  measured  from  d,  but  above  P,  as  at  r, 
where  a  line  drawn  from  the  center  of  gravity  g  of  the 
prism  of  maximum  pressure  d  i  k  (omitting  any  earth  rest- 
ing directly  upon  the  top  of  the  wall)  and  parallel  to  the 
line  d  k  oi  maximum  pressure  cuts  the  back  b  d  oi  the  wall. 
The  center  of  pressure  P  will  be  at  ^  the  height  of  the  wall 
when  the  sustained  earth  d  b  s  ox  d  b  f  iorms,  a  complete  tri- 
angle^ one  of  whose  angles  is  at  b,  the  inner  top  edge  of  the 
wall.  For  all  other  surcharges,  the  point  of  pressure  will 
be  above  P. 

1490.  General    Directions    and    Precautions. — 

The  batter  of  the  face  of  the  wall  should  not  (unless  circum- 
stances require  it)  be  greater  than  \\  inches  to  the  foot. 
When  the  batter  is  greater,  the  joints  catch  more  or  less  of 
the  water  running  down  the  face,  which  is  carried  into  the 
joints,  tending  to  weaken  the  mortar.     All  mortar  used  in 


912 


RAILROAD   CONSTRUCTION. 


retaining  walls  should  have  some  admixture  of  cement,  es- 
pecially in  the  lower  courses  of  masonry.  Common  lime 
mortar  will  not  set  so  long  as  it  is  kept  wet  by  the  moisture 
which  comes  from  the  foundation  and  the  moist  earth  back- 
ing. If  allowed  to  remain  long  in  this  condition,  it  becomes 
worthless.  When  the  batter  is  considerably  greater  than  1^ 
inches  to  the  foot,  the  water  may  be  excluded  from  the  joints 
by  careful  pointing. 


EXCAVATION. 

1491.  Earth  Work. — Earth  work  embraces  the  exca- 
vation of  all  earthy  material  included  within  the  section  of 
the  roadway  above  the  grade  line  and  the  transporting  and 
depositing  of  it  upon  those  sections  of  the  roadway  below 
the  grade  line,  forming  the  embankment.  It  also  includes 
all  excavations  for  foundations  above  the  water-line,  the 
cutting  of  ditches,  changing  of  watercourses,  and  all  excava- 
tion ordinarily  required  in  the  formation  and  protection  of 
the  roadway.  Those  parts  of  the  roadway  formed  by  ex- 
cavation are  called  cuts  and,  according  to  their  various  sec- 
tions, are  called  through  cuts,  those  in  which  the  entire 
width  of  the  roadway  is  in  excavation,  and  side  cuts,  in 
which  only  a  part  of  the  roadway  is  in  excavation  and  a  part 
in  embankment. 

Ordinarily  the  side  slopes  in  excavation  are  made  at  an 


FIG.  409. 

inclination  of  1  horizontal  to  1  vertical,  and  the  side  slopes 
of  embankments  at  an  inclination  of  1^  horizontal  to  1  verti- 
cal.    The  slopes  for  cuts  in  the  alluvial  soils  of  our  western 


RAILROAD   CONSTRUCTION. 


913 


prairies  are  commonly  made  1^  horizontal  to  1  vertical,  on 
account  of  their  small  resistance  to  frost  and  water.  Fig. 
409  represents  a  section  of  a  through  cut,  Fig.  410  a  com- 


FlG.  410. 


plete  section  of  embankment,   and  Fig.  411  a  side  cut,   in 
which  part  is  excavation  and  part  embankment. 

Methods  in  handling  earth  vary  widely,  depending  upon 
the  character  of  material,  the  situation,  the  magnitude  of 


Fig.  411. 

the  work,  and  very  greatly  upon  the  contractor.  The  sec- 
tion of  roadway  shown  in  Fig.  411  admits  of  very  eco- 
nomical construction.  The  material  is  loosened  with  the 
plow  or  pick,  and  cast  by  hand  directly  from  the  cut  to  the 
adjacent  embankment. 

1492.  The  Use  of  a  Road  Machine. — A  more  ex- 
peditious and  economical  practice  is  to  handle  the  material 
with  a  road  machine.  A  road  machine  of  great  strength, 
especially  designed  for  railroad  use,  is  much  used  for  work 
of  this  character.  The  blade  of  the  machine  cuts  and 
scrapes  the  material  from  the  higher  points  and  carries  it 


914  RAILROAD   CONSTRUCTION. 

along,  depositing  it  in  the  low  places.  An  experienced  fore- 
man, with  a  good  and  well-manned  machine,  can  almost 
complete  the  work  on  a  side  hill  line,  leaving  only  a  little 
trimming  and  ditching  to  be  done  by  hand.  Before  using 
the  road  machine,  the  ground  is  broken  with  a  plow.  Earth 
under  favorable  conditions  can  be  handled  by  road  machines 
at  from  10  to  12  cents  per  cubic  yard.  A  plow  especially 
designed  for  loosening  earthy  material  is  called  a  "railroad 
plow."     It  is  amply  strong  enough  to  stand  the  draft  of 


Fig.  412. 
three  heavy  teams,  and  is  an  important  part  of  a  grading 
outfit.     Fig.  412  shows  a  good  form  of  a  railroad  plow. 

1493.  Wheel  bar  ro^w  Work. — The  transportation  of 
earth  by  wheelbarrows  has  of  late  years  been  practically 
abandoned  by  the  more  progressive  contractors.  There  are, 
however,  situations  where  they  may  be  used  to  advantage. 
When  the  haul  is  short  and  the  work  difficult  of  access  to 
teams,  the  pick,  shovel,  and  wheelbarrow,  on  account  of  their 
portability,  are  brought  into  use. 

It  frequently  happens,  especially  after  protracted  rains, 
that  teams  can  not  be  used  on  account  of  miring.  Under 
such  conditions,  the  work  can  be  carried  on  with  wheel- 
barrows. A  runway  of  planks  under  all  circumstances  is 
necessary  to  secure  a  firm  and  even  tread  for  the  wheels. 

In  wheelbarrow  work,  each  man  loads  his  own  wheelbar- 
row. A  sufficient  number  of  pickers  must  be  employed  to 
keep  a  constant  supply  of  loosened  material.  The  gangway 
planks  must  be  kept  smooth,  in  order  that  there  may  be  no 
impediment  to  wheeling.  A  wheelbarrow  carries  y'y  of  a 
cubic  yard  of  ordinary  material.    The  men  in  wheeling  move 


RAILROAD   CON*STRUCTION.  915 

at  the  rate  of  about  200  feet  per  minute,  or  2^  miles  per  hour, 
which  is  equivalent  to  100  feet  each  way  per  minute,  techni- 
cally called  100  feet  of  lead.  The  length  of  time  required  in 
making  a  round  trip  from  the  pit  (as  the  place  of  excavation 
is  called)  to  the  dump  will  be  as  many  minutes  as  there  are 
100  feet  of  lead;  to  which  must  be  added  1:^^  minutes  for 
loading  and  dumping.  Delays  of  various  kinds  are  met  with, 
which  will  consume  about  yV  of  the  time;  so  that  in  calcu- 
lating the  number  of  trips  which  each  man  will  make  in  a 
day  the  total  number  of  minutes  in  a  working  day  of  10 
hours,  viz.,  600  minutes,  must  be  reduced  by  60  minutes, 
leaving  540  minutes  for  actual  work.  We  will,  therefore, 
have 

the  number  of  trips  for  each  man  per  day  = 

540 

1.25  +  the  number  of  100  feet  lengths  of  lead' 

Example. — Allowing  $1.20  per  day  as  wages  for  men,  what  will  be 
the  cost  to  the  contractor  for  handling  earth  with  wheelbarrows,  the 
lead  being  500  feet  ? 

Solution. — The  number  of  trips  per  day  =  tj-^^ =  =  86.4  trips. 

As  14  trips  are  required  for  each  cubic  yard  of  material,  the  number 

of  cubic  yards  handled  per  day  per  man  =  -zrj-  =  6.17  cubic  yards,  and 

the  cost  per  cubic  yard  to  the  contractor  for  loading  and  wheeling  will 

§1.20 
be  -K-ry  =  19.45  cents  per  cubic  yard. 

It  will  require  one  picker  for  each  5  wheelbarrows.  Five  wheel- 
barrows will  handle  6.17x5  =  30.85  cubic  yards.  Consequently,  we 
must  add  to  the  above  cost  per  cubic  yard  §1.20,  the  wages  of  the 

1.20 
picker,  divided    by   30.85,    the   number  of    yards    loosened,  = 

3.89  cents. 

In  addition  to  the  above  items,  there  must  be  added  the  wages  of  a 

foreman  and  water  carrier,  one  each  for  a  gang  of  30  men,  of  which  24 

handle  wheelbarrows.     A  foreman  will  cost  $2.50  per  day  and  water 

carrier  $1.00  per  day,  making  $3.50  per  day.     The  additional  charge 

$3  50 
against  each  wheelbarrow  will,  therefore,  be       '      =  14.59  cents,  and 

this  sum  divided  by  the  number  of  cubic  yards  carried  by  each  wheel- 
barrow will  give  amount  to  be  added  to  each  cubic  yard  for  superin- 

14-  tSQ  cpnts 
tendence  and  water  carrier,  or  — "       _ =  2.36  cents  per  eubic  yard. 


916  RAILROAD   CONSTRUCTION. 

Placing  the  various  items  of  cost  in  order,  we  have 

Cost  of  wheeling    19.45  cents  per  cu.  yd. 

Cost  of  picking  3.89  cents  per  cu.  yd. 

Cost  of  foreman  and  water  carrier 2.36  cents  per  cu.  yd. 

Wear  of  tools  and  wheelbarrows 50  cent    per  cu.  yd. 

Total  cost  to  contractor 26.20  cents  per  cu.  yd. 

Add  15  per  cent,  for  contractor's  profit. .  3.93  cents  per  cu.  yd. 

Cost  to  R.  R.  Company  30. 13  cents  per  cu.  yd. 

A  contractor  can  not  undertake  wheelbarrow  work  under 
30  cents  per  cubic  yard,  which  is  much  in  excess  of  prices 
paid  for  earth  excavation  for  railroad  work  in  1804-5.  If, 
however,  the  contractor  is  enabled  through  the  use  of  the 
wheelbarrow  to  do  work  which  would  be  difficult  to  accom- 
plish without  it,  its  value  is  at  once  manifest,  and  losses  which 
he  may  suffer  on  sections  requiring  wheelbarrow  work  he 
can  readily  make  good  on  sections  admitting  of  more  modern 
methods. 

1494.  Cart  Work. — The  cost  of  loading,  hauling,  and 
dumping  material  by  carts  may  be  calculated  in  the  same 
way  as  in  calculating  cost  by  wheelbarrows.  An  ordinary 
earth  cart  weighs  about  ^  ton  and  will  carry  on  an  average 
^  cubic  yard  of  the  various  soils  encountered  in  railroad  con- 
struction, measured  in  place  before  being  loosened.  The 
material  to  be  excavated  is  loosened  in  two  ways,  viz.,  by 
pick  and  by  plow.  When  picks  are  used,  the  cut  is  taken  out 
complete  to  grade,  commencing  where  the  grade  line  cuts 
the  surface  of  the  ground  and  working  backwards,  the  ma- 
terial being  hauled  and  dumped  to  form  the  adjacent  em- 
bankment. The  carts  are  backed  up  to  the  breast  of  the 
cut  (as  it  is  called),  and  the  material  loaded  with  shovels.  A 
shoveler  can  shovel  ^  cubic  yard  of  sandy  soil  into  a  cart  in 
about  5  minutes;  of  loam,  in  6  minutes,  and  of  heavy  clayey 
soil,  in  7  minutes.  By  working  constantly  without  any  de- 
lays, he  could  shovel  in  a  day  of  10  hours,  or  600  minutes,  of 
light  sandy  soil,  120  loads;  of  loam,  100  loads,  and  of  heavy 
soil,  86  loads.  He  will,  however,  lose  about  y\  of  his  time 
through  delays  in  waiting  for  carts  and  from  other  causes. 
The  cost  of  loading  carts  is  determined  as  follows:     600,  the 


RAILROAD    CONSTRUCTION.  917 

whole  number  of  minutes  in  a  working  day,  less  180  minutes 
lost  through  delays,  leave  420  minutes  actually  employed  in 

work;  and  — —  =  84,  the  number  of  cart  loads  of  light  sandy 

0 

420 
soil  which  will  be  a  day's  work  for  one  shoveler;  — -  =  70, 

420 
the  number  of  loads  of  loam,  and  — —  =  00,  the  number  of 

loads  of  heavy  soil.     The  cost  of  shoveling  into  carts,  with 

1.20 
wages  at  $1.20  per  day,   will  be,    respectively,   -^-j— =1.43 

84 

1  20 
cents  per  load  for  sandy  soil;  -^—-  =  1.71  cents  per  load  for 

1  20 
loam,  and  -——  =  2  cents  per  load  for  heavy  soil.  As  it  re- 
quires 3  loads  to  make  one  yard,  the  cost  for  shoveling  per 
cubic  yard  will  be  1.43  X  3  =  4.29  cents  per  cubic  yard  for 
sandy  soil;  1.71  X  3  ==  5.13  cents  per  cubic  yard  for  loam, 
and  2x3  =  0  cents  per  cubic  yard  for  heavy  soil.  The  cost 
of  picking  will,  of  course,  be  the  same  as  that  given  in  Art. 
1493  for  the  wheelbarrow  work,  viz.,  3.89  cents  per  cubic 
yard.  A  horse  will  haul  a  cart  at  the  rate  of  about  2^  miles 
per  hour,  equivalent  to  200  feet  per  minute,  or  100  feet  going 
and  coming  per  minute,  i.  e.,  1  minute  for  each  100  feet  of 
lead.  Besides  the  time  consumed  in  going  and  coming  to 
and  from  the  dump,  there  is  a  loss  of  about  4  minutes  to 
each  trip,  which  time  is  consumed  in  loading,  turning,  and 
dumping.  The  number  of  trips  per  day  for  each  cart  will, 
therefore,  be  the  number  of  minutes  in  a  working  day  divi- 
ded by  4  plus  the  number  of  100  feet  lengths  of  lead.  For 
example,  suppose  the  lead  is  800  feet,  we  will  then  have 

number  of  cart  trips  per  day  =  =  50  trips. 

•±  -\-  o 

As  1  cubic  yard  of  material  in  place,   i.    e.,  before  being 

loosened,  will  make  3  cart  loads,  the  number  of  cubic  yards 

transported  by  each  cart  per  day  will  be  the  number  of  cart 

50 
loads  handled    divided    by  3.     Accordingly,    we   have  —  = 

o 


918  RAILROAD    CONSTRUCTION. 

16.66  cubic  yards,  a  day's  work  for  each  cart.  With  labor 
at  $1.20  per  day,  the  expense  of  a  horse  will  be  about  $1.00, 
the  use  of  cart  and  harness  25  cents,  and  as  1  driver  at  $1.00 
per  day  can  attend  to  4  carts,  the  total  charge  against  each 
cart  will  be 

Horse $1.00 

Cart  and  harness.  .  : 25 

Driver .     .25 

Total $1.50 

The  cost  of  hauling  per  cubic  yard  will,  therefore,  be  the 
cost  of  cart  divided  by  the  number  of  cubic  yards  hauled, 

and  we  have  ^  /       =  9  cents  per  cubic  yard. 
10.60 

A  man  is  constantly  employed  on  the  dump  to  assist  in 
dumping  the  carts  and  spreading  material  in  layers,  which 
will  cost  an  average  of  1  cent  per  cubic  yard.  A  gang  of  10 
carts  will  require  1  foreman  at  $2.50  per  day  and  water  car- 
rier at  $1.00  per  day.  The  cost  per  cubic  yard  for  superin- 
tendence and  water  carrier  will,  therefore,  be  $3.50  divided 
by  the  total  number  of  cubic  yards  hauled  by  10  carts.  Each 
cart  hauls  16.66  cubic  yards,  and  10  carts  will  haul   16.66 

X  10  =  166.6  cubic   yards  and     '  '   ^  =2.1  cents  per  cubic 

160.0 

yard. 

In  hauling  loam,  the  amount  of  the  foregoing  items  of  cost 
per  cubic  yard  will  be: 

Loosening 3.89  cents  per  cubic  yard. 

Shoveling 5.13  cents  per  cubic  yard. 

Hauling 9.00  cents  per  cubic  yard. 

Dumping  and  spreading.  1.00  cent    per  cubic  yard. 

Superintendence 2.10  cents  per  cubic  yard. 

Add  for  sharpening  and 

use  of  tools 50  cent    per  cubic  yard. 

Total  cost  to  contractor  21.62  cents  per  cubic  yard. 

Add  15  per  cent,  for  con- 
tractor's profit 3.24 

Cost  to  R.  R.  Company  24.86  cents  per  cubic  yard. 


RAILROAD   CONSTRUCTION. 


919 


The  items  given  are  supposed  to  include  repairs  of  cart 
roads  (a  very  important  matter)  and  the  trimming  and 
ditching  of  cuts.  The  cart,  like  the  wheelbarrow,  is  becom- 
ing obsolete  in  modern  railroad  construction.  Its  place  is 
being  taken  by  road  machines,  wheeled  scrapers,  dump  cars, 
and  steam  excavators.  The  pick  and  shovel  are  still  largely 
used,  especially  on  the  western  plains.  Hundreds  of  miles 
of  road  are  built  on  the  level  prairies  by  casting,  that  is,  by 
shoveling  the  material  directly  from  borrow  pits  at  the  side 
of  the  roadway  into  the  embankment.  The  soil  is  generally 
soft  enough  to  move  without  the  use  of  a  pick,  and  often  for 
miles  the  expense  of  hauling  is  entirely  saved.  Under  such 
conditions  earth  may  be  handled  at  from  14  to  16  cents  per 
'cubic  yard  at  fair  profit.  The  embankment  on  such  sections 
has  an  average  height  of  about  2  feet.  Not  an  economic  in- 
vestment for  the  bondholders  of  the  road,  but  it  is  often 
very  profitable  for  those  who  sell  the  bonds. 

1495.  Wheeled  Scraper  ^Vork.— The  body  of  the 
wheeled  scraper  (see  Fig.  413)  is  of  sheet  steel  about  3^ 


Fig.  413. 


feet  square  and  15  inches  deep,  containing  about  ^  cubic 
yard  when  level  full.  The  box  is  open  in  front,  and  can  be 
raised   or  lowered  and  revolves  on  a  horizontal  axis.     All 


920  RAILROAD   CONSTRUCTION. 

movements  of  the  box  are  made  by  means  of  levers.  In  load- 
ing, the  box  is  lowered  so  that  the  cutting  edge  of  the  open 
front  cuts  into  the  ground.  A  strong  team,  and  usually  a 
second  team  called  a  snatch  team,  haul  the  scraper,  which  fills 
itself  in  the  same  way  as  an  ordinary  hand  shovel  is  filled. 
When  full,  the  box  is  raised  about  1  foot  from  the  ground 
by  means  of  a  lever,  and  the  snatch  team  is  detached.  The 
loaded  scraper  is  then  hauled  to  the  dump,  the  dumping 
being  effected  by  means  of  a  lever,  without  stopping  the 
team,  which  is  constantly  moving.  The  wheels  have  broad 
tires,  which  prevent  their  cutting  into  the  ground.  Where 
wheeled  scrapers  are  used,  the  material  is  always  loosened 
with  a  plow.  The  cut  is  not  worked  from  a  breast,  as  with 
carts,  but  is  taken  out  in  successive  layers  from  the  full  area 
of  the  cut. 

The  scrapers  are  loaded  while  the  teams  are  moving,  and 
as  they  are  continually  in  motion,  their  rate  of  speed  will  be 
somewhat  slower  than  with  carts  or  wagons.  Taking  the 
rate  of  movement  of  scrapers  at  150  feet  per  minute,  the 
distance  traveled  in  going  and  coming  will  be  but  75  feet 
per  minute,  or  75  feet  of  lead  per  minute.  Besides  the 
actual  length  of  lead,  each  team  will  travel  about  25  feet 
additional  in  turning  and  dumping.  Hence,  the  number  of 
trips  for  each  wheeled  scraper  per  day  will  be  the  total  num- 
ber of  minutes  in  a  working  day,  viz.,  GOO  divided  by  the 
number  of  75  feet  lengths  in  the  lead  -f-  25  feet,  and  suppo- 
sing, for  example,  there  is  a  total  lead  of  800  feet,  the  number 

i  ^  ■  '         A  -11  K     600      600       _  . .      . 

of  trips  per  scraper  per  day  will  be  — —  =  -— —  =  54.54  trips 

oZo  11 

per  day,  and  the  number  of  cubic  yards  for  each  scraper 

^  J.    '^  J- 

will  be  — - —  =  27.27  cubic  yards  per  day. 
z 

It  will  cost  an  average  of  1  cent  per  cubic  yard  to  loosen 

soils  and  1  cent  per  cubic  yard  to  load  and  dump  them.     An 

additional  charge  of   -^\  cent  per  100  feet  of  lead  must  be 

made  for  keeping  the  road  in  order. 


RAILROAD   CONSTRUCTION. 


921 


Spreading,  water  carrier,  and  superintendence  will  cost 
2  cents  per  cubic  yard.  A  man  and  team  will  cost  13.50, 
with  50  cents  added  for  snatch  team,  making  14.00  per  day, 
the  charges  against  each  scraper  for  hauling.     We  have, 

therefore,  the  cost  of  hauling      '      =  14.67  cents  per  cubic 

yard. 

For  handling  ordinary  earthy  material  with  wheeled 
scrapers,  the  amount  of  the  foregoing  items  of  cost  will  be 
as  follows: 

Loosening  with  the  plow 1.00  cent    per  cubic  yard. 

Loading  and  dumping 1.00  cent    per  cubic  yard. 

Hauling. 14.67  cents  per  cubic  yard. 

Maintaining  road  at  a  cost  of  ^ 

cent  for  each  100  ft.  of  lead.  . .  .80  cent  per  cubic  yard. 
Superintendence,   water   carrier, 

and  spreading ....   2.00  cents  per  cubic  yard. 

Total  cost  to  contractor. .  .19.47  cents  per  cubic  yard. 
Adding      15^     for     contractor's 

profit 2.92  cents  per  cubic  yard. 

Cost  to  R.  R.  Company 22.39  cents  per  cubic  yard. 

1496.     Drag    Scraper    W^ork. — The  drag  scraper 

(see  Fig.  414)  holds   from    .15  to  .25   of  a  cubic  yard   of 

material.     The    same    labor 

of  horse  and  man  is  required 

for    the   drag  scraper  as  for 

the  wheeled  scraper,  except- 

^  ing   the   snatch  team.     The 

team     will      move      at     the 

same  rate,   viz.,   75    feet    of 

lead    per    minute,    but   only 

15    feet   need    be    added    to 

the    lead    for    dumping    and 
Fig.  414.  ^         .  T>w 

turnmg.     Drag  scrapers  are 

rarely  used  for  a  longer  haul  than  400  feet. 


922 


RAILROAD   CONSTRUCTION. 


RAILROAD   CONSTRUCTION.  923 

The  number  of  trips  in  a  day  for  a  400-foot  lead  will,  there- 

600  (number  of  minutes  in  day)       _600_  600  _ 

'        number  of  75  feet  length  in  lead -|- 15  ~~  415      5.53~ 

108.5  trips  at  ^  cu.  yd.  per  trip  =  21.7  cubic  yards,  the 
amount  of  material  hauled  by  each  team  per  day.  As  the 
team  and  driver  cost  $3.50  per  day,  the  cost  of  hauling 

per  cubic  yard  will  be  -^^t-^  =  16.13  cents.     Other  charges 

will  be  the  same  for  drag  scrapers  as  for  wheeled  scrapers, 
and  we  have  the  items  giving  total  cost  to  contractor  fof 
delivering  material  at  the  dump,  as  follows: 

Loosening  with  plow. 1.00  cent  per  cubic  yard. 

Loading  and  dumping 1.00  cent  per  cubic  yard. 

Hauling 16.13  cents  per  cubic  yard. 

Maintaining  road,  yVcent  for 

each  100  feet  of  lead.  . .  .40  cent  per  cubic  yard. 

Superintendence,  water  car- 
rier, and  spreading.  ...  2.00  cents  per  cubic  yard. 

Total  cost  to  contractor, 

exclusive  of  profit.  ....  20.53  cents  per  cubic  yard. 
Add    15^    for    contractor's 

profit 3.08  cents,  per  cubic  yard. 

Total  cost  to  R.  R.  Com- 
pany   23.61  cents  per  cubic  yard. 

The  above  figures  are  only  approximate,  and  will  vary 
largely  with  conditions.  Much  depends  upon  the  material 
handled,  the  situation,  and  the  weather;  but  far  more  upon 
the  energy,  skill,  and  judgment  of  the  contractor  and  fore- 
man. 

1497.  Work  with  a  Steam  Excavator  and  Dump 
Cars. — In  cuttings  from  8  feet  upwards,  a  steam  excavator 
may  be  employed  to  great  advantage.  A  first-class  exca- 
vator, such  as  is  shown  in  Fig.  415,  will  excavate  and  load 
into  dump  cars  600  cubic  yards  per  day. 


924  RAILROAD    CONSTRUCTION. 

The  excavator  stands  on  a  track  a,  and  as  the  material 
ahead  of  the  machine  is  cut  away,  the  track  is  extended  and 
the  excavator  is  advanced  by  means  of  its  own  machinery. 
This  is  accomplished  as  follows:  The  car  axles  b,  b  are  fitted 
with  sprocket  wheels  driven  by  pitch  chains  c.  These 
chains  work  on  sprocket  wheels  d^  fixed  to  the  countershaft  e. 
The  countershaft  carries  a  pinion,  not  seen  in  the  drawing, 
which  is  driven  by  the  large  spur/',  which  is  itself  driven  by 
a  pinion  attached  to  the  main  shaft  g.  The  main  shaft  also 
carries  another  pinion  which  drives  the  spur  //,  and  the 
drum  attached  to  its  shaft.  This  drum  carries  the  chains  k 
which  give  to  the  crane  /  its  lateral  motion.  The  boom  m 
is  formed  of  heavy  steel  angles,  between  which  the  dipper 
handle  n  works.  The  power  for  crowding  the  dipper  out- 
wards is  applied  through  the  steel  rack  and  the  pinion 
attached  to  the  dipper  shaft,  and  derived  from  the  hoisting 
chain  q,  where  it  passes  over  a  pocket  sheave  r.  This 
pocket  sheave  drives  the  intermediate  shaft  s  by  friction 
clutch  and  steel  pitched  chain. 

The  dipper  /  holds  from  1  to  If-  cubic  yards.  The  teeth 
are  of  heavy  pointed  steel  and  attached  so  as  to  be  renew- 
able. The  handle  is  of  oak  with  racking  of  heavy  cast  steel. 
Steam  is  generated  in  the  boiler  w,  and  the  machinery  is 
driven  by  the  engine  v.  The  reversing  levers  are  shown 
at  w.  The  excavator  crew  consists  of  three  men,  viz.,  an 
engineer,  foreman,  and  craneman.  The  duty  of  the  latter 
is  to  see  that  the  excavator  does  full  work,  i.  e.,  that  the 
dipper  is  filled  at  each  cut  of  the  machine.  Six  pitmen  are 
required  to  lay  track,  see  to  the  shifting  of  the  machine, 
and  help  in  shifting  cars  and  making  up  train  loads.  The 
bulk  of  the  work  connected  with  the  shifting  of  cars  and 
making  up  of  trains  is  performed  by  horsepower. 

A  pit  foreman  takes  charge  of  all  work  not  immediately 
connected  with  the  working  of  the  excavator.  The  cost  of 
an  excavator  is  about  $6,000.  For  interest  on  same  and 
wear  and  tear  of  machine,  charge  110.00  per  day. 

The  several  items  of  cost  to  be  charged  to  the  excavator 
will  be  the  following: 


RAILROAD   CONSTRUCTION.  925 

Cost  of. excavator $10.00  per  day. 

1^  tons  coal  @  16.00  per  ton 9.00  per  day. 

Water 4.00  per  day. 

Oil,  waste,  etc 3.00  per  day. 

Engineer 4. 50  per  day. 

Fireman 2.00  per  day. 

Craneman 3.00  per  day. 

6  pitmen  @  $1.50 9.00  per  day. 

Foreman 3.00  per  day. 

Horse  and  driver  for  shifting  cars.  .  2.25  per  day. 

Total ; $49.75 

At  600  cubic  yards  per  day,  the  cost  per  cubic  yard  for 

$49  75 
excavating  will  be        '       =  8.29  cents. 

Teams  will  haul  6  cars  holding  1^  cubic  yards  each  and 
travel  at  the  rate  of  3  miles  per  hour,  or  an  average  of  about 
260  feet  per  minute,  which  will  bean  average  of  130  feet  go- 
ing and  coming,  i.  e.,  130  feet  of  lead  per  minute.  About 
3  minutes  are  consumed  in  stopping,  dumping,  and  chang- 
ing team  for  return  to  the  excavator.  It  will  require  about 
1:^  minutes  per  car  to  load,  making  9  minutes  per  train  of 
6  cars.  The  number  of  trips  per  team  per  day  will,  there- 
fore, be  equal  to  600,  the  number  of  minutes  in  a  working 
day  of  10  hours,  divided  by  9  minutes,  the  time  of  loading  + 
3  minutes,  the  time  of  unloading  +  the  number  of  130  feet 
lengths  of  lead.  Calculating  upon  a  haul  of  1,300  feet  equal 
to  ten  130  feet  lengths  of  lead,  we  have  the  number  of  trips 

per  team  per  day  =  -————— =  27.3.     Deducting  for  de- 
y  — |—  o  ~j~  j-U 

lays  caused  by  defective  track,  derailed  cars,  etc.,  3.3  trips, 
we  have  24  trips  per  day  for  each  team.  As  each  train  car- 
ries 9  cubic  yards,  the  total  yardage  per  team  per  day  is 
24  X  9  =  216  cubic  yards.     The  team  and  driver  will  cost 

$3  75 
$3.75  per  day.    The  cost  for  hauling  will,  therefore,  be     ' ' 

=  1. 74  cents  per  cubic  yard.  Five  men  are  required  to  main- 
tain the  tracks  and  take  charge  of  the  dump,  4  men  at  $1.25 


926  RAILROAD   CONSTRUCTION. 

per  day  and  foreman  at  $2  per  day,  making  17.00  per  day. 
The  cost  per  cubic  yard  for  track  and  dump  charges  will, 

therefore,  be  -^—  =  1.17  cents  per  cubic  yard.  It  will  re- 
quire 24  cars  to  handle  the  materials,  at  a  cost  of  50  cents 
per  car  per  day,  making  a  total  daily  charge  of  $12.00,  which, 
divided  by  600,  gives  an  additional  charge  of  2  cents  per 
cubic  yard  for  use  of  cars.  The  total  cost  to  the  contractor 
for  excavating,  loading,  hauling,  dumping,  and  spreading 
will,  therefore,  be  as  follows: 

Excavating  and  loading 8.29  cents  per  cubic  yard. 

Hauling 1.74  cents  per  cubic  yard. 

Care    of     track,     dumping,     and 

spreading 1.17  cents  per  cubic  yard. 

Use  of  cars 2.00  cents  per  cubic  yard. 

Total  cost  to  contractor 13.20  cents  per  cubic  yard. 

Adding     25;^     for     contractor's 

profit 3. 30  cents  per  cubic  yard. 

Cost  to  R.  R.  Company 16.50  cents  per  cubic  yard. 

On  account  of  the  great  cost  of  plant  and  heavy  contin- 
gent expenses,  the  contractor  should  calculate  on  a  profit  of 
25  per  cent,  when  making  estimates  on  this  class  of  work. 

1498.  Rock  Excavation. — A  cubic  yard  of  hard  rock 
in  place,  i.  e.,  before  being  blasted,  weighs  on  an  average 
1.9  long  tons,  or  4,256  lb.,  equal  to  158  pounds  per  cubic  foot. 
A  cubic  yard  of  hard  or  solid  rock  w/irn  broken  up  by  blasting 
so  that  it  may  be  loaded  into  carts  will  occupy  about  1.8  cubic 
yards  of  space,  or  48.6  cubic  feet  of  space.     Each  cubic  foot 

of  broken  rock  will,  therefore,  weigh    '  =  87. 6  lb.  A  cart 

will  carry  about  -^  of  a  cubic  yard  of  solid  rock,  i.  e.,  9.7  cubic 
feet  of  broken  rock,  which  will  weigh  on  an  average  850  lb., 
which  is  only  50  lb.  more  than  an  average  cartload  of  earth. 
A  horse  may,  therefore,  be  expected  to  haul  as  many  loads 
of  broken  rock  as  of  earth.  It  will  cost  on  an  average 
40  cents  per  cubic  yard  in  place  to  cover  the  cost  of  loosen- 


RAILROAD   CONSTRUCTION.  927 

ing,  including  sharpening  tools,  drilling,  powder,  etc.  It 
will  cost  an  average  of  10  cents  per  cubic  yard  in  place  to 
load  the  stone  into  carts.  As  the  number  of  cubic  yards  of 
rock  handled  per  day  is  less  than  the  number  of  cubic  yards 
of  earth,  the  cost  of  superintendence  and  of  water  carrier 
will  be  greater,  say  3  cents  per  cubic  yard.  Repairs  of  road 
will  cost  ^  cent  for  each  100  feet  of  lead.  Dumping  and 
spreading  will  cost  2  cents  per  cubic  yard.  Carts  will  cost 
same  as  in  earth  excavation,  viz.,  $1.50  per  day.  It  will 
require  an  average  of  5  minutes  to  load  and  dump  carts. 

Example. — For  a  lead  of  600  feet,  what  will  be  the  cost  to  the  con- 
tractor for  delivering  solid  rock  on  the  dump  ? 

Solution. — The  number  of  cart  trips  per  day  will  be  600,  the 
number  of  minutes  in  a  working  day,  divided  by  5  +  the  num- 
ber of  100  feet   lengths  of  lead.     We  have,  accordingly,  number  of 

cart  trips  per  day  =  ;; ^  =  54.5  trips.     At  ^  cubic  yard  per  cart,  the 

54  5 
number  of  cubic  yards  hauled    per  cart  per  day  will  be  —^  =  10.9 

cubic  yards  in  place.  The  cost  of  hauling  will,  therefore,  be  $1.50,  the 
cost  per  day  per  cart,  divided  by  10.9,  the  number  of  cubic  yards 
hauled  per  cart,  which  gives  13.76  cents  per  cubic  yard  in  place,  that 
is,  of  solid  rock.  We  have  then  for  handling  solid  rock  with  carts, 
the  following  items  of  cost,  viz.  : 

Loosening 40.00  cents  per  cubic  yard. 

Loading 10.00  cents  per  cubic  yard. 

Hauling 13.76  cents  per  cubic  yard. 

Dumping  and  spreading 2.00  cents  per  cubic  yard. 

Superintendence  and  water  car- 
rier      3.00  cents  per  cubic  yard. 

Repairs  of  road 1.20  cents  per  cubic  yard. 

Total  cost  to  contractor 69.96  cents  per  cubic  yard. 

Add  15  per  cent,  for  contractor's 

profit 10.49  cents  per  cubic  yard. 

Cost  per  cubic  yard  to  the  R.  R. 
Company 80.45  cents  per  cubic  yard. 

All  stone  and  detached  rock  found  in  separate  masses,  con- 
taining not  less  than  3  cubic  feet  nor  more  than  1  cubic  yard, 
and  all  masses  of  rock,  slate,,  or  coal,  or  other  rock  soft 
enough  to  be   removed   without  blasting,  are  classified   as 


928  RAILROAD   CONSTRUCTION. 

loose  rock  and  may  be  handled  at  about  half  the  cost  of 
solid  rock. 

1 499.  Hand  Drilling:. — Hand  drilling  is  performed  in 
two  ways,  viz.,  by  churn  drilling  and  by  Jumping.     A 

churn  drill  is  made  of  a  round  iron  bar  about  1^  inches  in 
diameter  and  from  6  to  8  feet  in  length,  having  a  piece  of 
tool  steel  a  little  wider  than  the  diameter  of  the  bar  welded 
to  one  end  of  it.  This,  after  being  properly  hardened  and 
sharpened,  forms  the  cutting  edge.  In  ordinary  work,  the 
holes  are  from  1^  to  3  inches  in  diameter  and  from  2  to  4  feet 
in  depth.  Holes  drilled  with  the  churn  drill  are  usually 
vertical.  In  drilling  the  bench  in  tunnel  work  the  drills  are 
inclined  slightly  backwards  from  a  vertical  line.  In  drilling, 
the  churner  raises  the  drill  a  few  inches,  turning  it  slightly 
in  the  hole  and  allowing  it  to  fall.  The  drill  in  a  free,  hole 
rebounds  so  that  but  little  effort  is  required  by  the  driller 
in  lifting  the  drill.  An  experienced  driller  will  in  a  working 
day  of  10  hours  drill  from  5  to  12  feet  of  2-inch  hole,  de- 
pending upon  the  character  of  the  rock.  In  granite  or  hard 
limestone  from  7  to  8  feet  of  If-inch  hole  is  a  fair  day's 
work  and  from  9  to  10  feet  in  ordinary  sandstone.  When 
the  hole  is  more  than  -4  feet  in  depth,  two  men  are  put  to 
the  drill. 

The  Juniper  is  a  short  drill  which  is  held  and  turned  by 
a  man  in  a  sitting  posture  while  blows  from  8  to  12-lb.  ham- 
mers are  delivered  upon  the  head  of  the  drill  by  two  other 
men  called  strikers.  The  average  depth  of  a  hole  per  man 
is  considerably  greater  with  the  churn  drill  than  with  the 
jumper.  The  advantage  of  the  jumper  lies  in  its  admitting 
of  drilling  holes  at  any  angle  and  in  many  places  where  the 
churn  drill  could  not  be  worked  on  account  of  limited 
space.  In  drilling  with  jumpers,  drills  of  various  lengths 
are  used,  depending  upon  the  depth  of  hole.  Drill  bits  re- 
quire sharpening  at  each  G  to  8  inches  of  hole.  Great  skill  is 
required  in  tempering  in  order  that  the  drills  may  do  full  duty. 

On  surface  work,  good  d,rillers  are  paid  from  $1.50  to 
$1.75  per  day.     In  tunnel  work  from  $1.75  to  $2.00  per  day. 


RAILROAD   CONSTRUCTION.  929 

1 500.  Percussion  Drills. — Percussion  drills  are  usu- 
ally spoken  of  as  rock  drills,  and  are  built  to  be  driven  by 
steam,  compressed  air,  or  electricity.  They  should  be  de- 
signed for  hard  service,  such  as  sinking  shafts  and  drilling 
tunnels  in  the  hardest  rock.  They  should  strike  a  hard 
blow,  and  be  so  built  as  to  stand  the  most  severe  usage,  yet 
be  readily  kept  in  repair  with  the  facilities  available  in  re- 
gions remote  from  machine  shops.  They  must  stand  up  to 
the  work  of  pounding  a  hole  in  the  hardest  kind  of  rock  at 
the  rate  of  150,000  to  200,000  blows  a  day,  with  all  the 
shocks  and  jars  which  that  would  mean.  The  blow  should 
be  an  uncushioned  blow;  that  is,  in  steam  and  compressed 
air  drills,  the  exhaust,  during  the  forward  stroke,  should 
remain  open  until  the  blow  is  struck,  and  none  of  the  force 
of  the  blow  should  be  taken  up  by  a  cushion  of  steam  or  air 
in  the  front  end  of  the  cylinder.  The  bit  or  drill  proper 
must  hit  the  rock,  which  is  the  only  proper  cushioning,  and 
hit  it  before  the  pressure  enters  the  front  end.  Expansive 
working  of  the  steam  or  air  in  rock  drills,  as  has  been  at- 
tempted, is  a  mistake.  It  is  permissible  and  advisable  in 
engines  where  the  length  of  the  stroke  is  fixed  and  where 
the  weight  of  the  machine  is  not  of  very  great  account,  but 
in  a  rock  drill  the  object  is  to  get  the  hardest  possible  blow 
f.-om  the  smallest  cylinder  and  the  lightest  machine.  The 
smaller  and  lighter  the  machine,  the  less  space  required  for 
working  and  the  easier  handled.  The  value  of  a  hard  blow 
in  hard  rock  is  well  known.  The  average  drill  runner  is 
not  careful  to  keep  his  bits  sharp,  and  it  is  a  common  sight 
to  see  a  rock  drill  pounding  away  with  a  bit  which  has  no 
edge  at  all.  It  then  becomes  a  question  of  pounding  the 
rock  to  pieces  instead  of  cutting  it. 

A  hard  blow  will  do  this,  while  a  tappet  drill,  which  has 
the  force  of  the  blow  materially  checked  by  the  early  admis- 
sion of  pressure  to  form  a  cushion,  will  run  along  at  a  lively 
speed,  but  accomplish  very  little  in  proportion  to  power 
consumed.  Another  quality  a  rock  drill  must  have  is  the 
power  to  pull  the  bit  out  of  the  hole  as  well  as  to  drive  it  in, 
and  that  when  the  hole  is  blocky,  crooked,  or  muddy. 


930 


RAILROAD   CONSTRUCTION. 


The  best  rock  drills  on  the  market  are  the  Ingersoll- 
Sergeant  and  the  Rand  drills,  operating  by  steam  or  com- 
pressed air,  and  the  General  Electric  Co. 's  drill,  operating 
by  electricity.  Fig.  416  is  a  sectional  view  of  one  form  of 
a  drill  using  steam  or  compressed  air,  without  tripod  or 
column. 

The  principal  parts  are  as  follows:  1  is  the  cylinder.  At 
the  right  hand  or  "back"  end  of  the  cylinder  there  is  a 
washer  2,  and  a  buffer  3,  to  receive  the  piston  when  it 
strikes  at  this  end.  Immediately  behind  these  are  the 
"rotation  washer"  4,  and  the  "rotating  ratchet"  5,  both 
inside  of  the  back  cylinder  head  6.  To  the  left,  7  is  the 
brass  "rifle  nut,"  8  is  the  "rifle  bar,"  and  9  is  the  piston. 
The  rifle  nut  7  is  secured  to  the  piston  9  and  slides  back 

.17  i»^ 


Fig.  416. 

and  forth  with  it  over  the  rifle  bar  8.  This  compels  a 
relative  rotation  between  the  bar  and  the  piston,  but  as  the 
piston  is  very  much  the  heavier,  the  tendency  is  that  only 
the  bar  will  rotate.  It  is  controlled,  however,  by  the  rota- 
ting ratchet  5,  and  allowed  to  turn  only  in  one  direction. 
The  piston,  therefore,  must  turn  on  its  return  stroke,  and 
in  this  way  it  is  made  to  rotate  a  little  at  every  blow  and  so 
drive  the  bit  to  a  new  place.  At  the  extreme  left,  10  is  the 
piston  bushing  to  take  the  wear  off  the  bit.  The  key  11  is 
drawn  down  by  the  U  bolt  12,  and  so  clamps  the  bit.  The 
front  cylinder  head  13  and  the  gland  IJ^  are  both  in  halves. 
The  washer  15  and  the  buffer  10  ease  up  the  blow  when  the 
piston  strikes  here  On  top  we  have  the  steam  chest  17, 
the  steam  chest  covers  18,  valve  19,  valve  guide  20,  valve 
washers  21,  and  buffers  22.     The  "goose  neck  "  ^5  carries 


RAILROAD   CONSTRUCTION. 


931 


one  end  of  the  feed  screw,  which  is  driven  by  the  crank 
25  turned  by  hand. 

Fig.  417  represents  a  drill  mounted  on  a  tripod  and  ready 
for  work.  The  feed-screw  A  is  collared  at  its  upper  end  to 
the  frame  B  and  is  thus  prevented 
from  moving  longitudinally  when 
revolved  by  the  crank  fixed  to  its 
top.  Its  lower  end  works  in  a  nut 
fixed  to  the  cylinder,  which  last 
moves  longitudinally  backward  as 
the  crank  is  turned. 

The  drilling  is  begun  with  a  short 
drill  called  a  starter,  the  first  few 
blows  being  lightly  given  until  the 
hole  is  fairly  started,  when  the  full 
force  of  the  steam  is  turned  on. 
As  the  drill  penetrates  the  rock, 
the  cylinder  is  fed  forward  by  means 
of  the  feed-screw  A  as  far  as  the 
shell  permits.  The  steam  is  then 
shut  off  gind  the  drill  withdrawn  by  reversing  the  movement 
of  the  feed-screw.  A  longer  drill  is  then  substituted  and 
the  drilling  continued.  The  cutting  edges  of  the  bits  are 
necessarily  worn  by  the  drilling  and  constant  rotation  in  the 
hole  so  that  the  diameter  of  the  bottom  of  each  section  of 
hole  is  slightly  less  than  that  at  the  top ;. accordingly,  at  each 
change  of  drill,  one  is  selected  with  a  bit  from  ^  to  -^^ 
inch  narrower  than  the  one  removed. 

In  tunnel  driving,  the  drills  used  in  the  heading  are 
usually  mounted  on  columns,  similar  to  that  shown  in  Fig. 
418.  The  column  A  is  set  in  an  upright  position  near  the 
face  of  the  heading,  the  top  B  of  the  column  being  forced 
against  the  roof  of  the  tunnel  by  the  capstan  screws  C 
which  rest  in  special  castings  D  on  the  floor  of  the  heading. 
It  is  a  common  practice  to  place  strong  blocks  of  wood  on 
the  head  of  the  column  and  under  the  feet  of  the  capstan 
screws,  which  prevent  the  rock  supports  from  becoming 
loosened  by  the  continued  jarring  of  the  column,  due  to  the 


Fig.  417. 


932 


RAILROAD   CONSTRUCTION. 


working  of  the  drills.     The  arm  E  at  right  angles  to  the 
column  slides   up   or  down   the   column    by  means  of   the 

collar  F^  and  may  be  clamped 
in  any  position  by  the  clamp  G. 
The  drill  is  carried  on  this  arm 
and  revolves  about  it  as  an  axis, 
thus  giving  a  wide  range  of 
action.  Usually  two  drills  are 
mounted  on  each  column.  In 
sinking  shafts  and  driving  tun- 
nels, as  well  as  in  mine  work, 
compressed  air  is  used  instead  of 
steam,  which  loses  much  of  its 
pressure  through  condensation. 
The  use  of  compressed  air  greatly 
promotes  ventilation.  Percus- 
sion drills  are  tinder  a  pressure 
of  from  60  to  70  lb.  per  square 
inch.  In  one  hour  one  will  drill 
a  hole  from  2  to  2i^  inches  in 
diameter  and  from  4  to  10  feet 
in  depth,  depending  upon  the 
character  of  the  rock,  the  position 
of  the  strata,  and  the  size  of  the 
machine.  The  cost  of  drilling 
will  vary  from  8  to  20  cents  per 
FIG.  41B  lineal  foot. 


1501.  I>rill-bits  are  of  different  shapes,  being 
varied  to  suit  the  work  to  be  done.  For  uniform  hard  rock, 
the  bit  is  cross-shaped,  with  the  arms  of  equal  length  and  at 
right  angles  to  each  other.  For  seamy  rock,  the  arms  of 
the  bits  are  of  equal  length,  but  cross  each  other  X  fashion. 
For  soft  rock,  frequently  a  bit  with  a  Z-shaped  cutting  edge 
is  used. 

Fig.  419  shows  the  usual  form  of  drill-bit,  and  Fig.  420  the 
tool  for  sharpening  same.  On  surface  work,  a  drill  is 
usually  worked  by  one  man;  in  tunnel  work,  two  men  are 


RAILROAD   CONSTRUCTION. 


933 


commonly  employed.      The   man   in  charge  of  the  drill  is 
called  the  drill  runner  and  his  assistant  the  helper  or  tailer. 

II  m  Three  or  four  men  are  required 
I  I  in  moving  and  placing  the  larger 
i      ■   drills. 


1502.      Air  Compressors, — 

As  before  stated,  when  percussion 
drills  are  used  for  surface  work, 
they  are  operated  by  steam  which 
is  usually  generated  in  a  portable  fig.  420. 
boiler  and  conveyed  to  the  drills  through  iron 
pipes.  The  direct  connection  with  the  drills  is 
FIG.  419.  made  by  means  of  steam  Jiose.  When  the  work 
is  of  great  magnitude  and  confined  to  a  small  area,  a  sta- 
tionary boiler  of  adequate  size  is  set  up. 

When  compressed  air  is  required  for  working  the  drills,  as 
in  mine  or  tunnel  work,  air  is  forced  into  a  receiver  by  an 


Fig.  421. 

air  compressor  and  conveyed  thence  by  iron  pipes  and  steam 
hose  to  the  drills.  The  receiver  is  a  wrought-iron  cylinder, 
from  2  to  4  feet  in  diameter  and  from  5  to  12  feet  long.  A 
cut  of  a  light  duplex  compressor  made  by  the  Rand  Drill  Co. 
is  shown  in  Fig.  421.     It  is  so  made  that  it  can  readily  be 


934 


RAILROAD   CONSTRUCTION. 


taken  apart  and  transported  on  mule-back.  A  and  B  are 
the  steam  cylinders,  and  C  and  D  are  the  air  cylinders.  E 
is  the  air  delivery  pipe  and  F  the  steam  pipe.  Some  of  the 
advantages  of  the  duplex  type  are  the  following:  Since  the 
cranks  are  set  at  right  angles,  the  engine  can  not  get  on  a 
dead  center.  One  cylinder  can  be  detached  when  only  half 
the  capacity  of  the  machine  is  required.  The  power  and 
resistance  being  equalized  through  opposite  cylinders,  large 
fly-wheels  are  not  necessary. 

A  borizontal  air  receiver  is  shown  in  Fig.  422.  The 
air  enters  the  receiver  at  A,  flows  through  a  series  of  pipe 
coils,  and  discharges  through  B.     Cold  water  constantly  cir- 


FlG.  422. 

culates  about  these  coils,  cooling  the  air  and  drying  it  at  the 
same  time,  the  moisture  dropping  to  the  bottom  of  the  coils. 
The  glass  gauge  £  indicates  the  amount  of  moisture  de- 
posited. When  the  gauge  indicates  too  great  an  accumu- 
lation of  water,  it  is  drained  off.  The  cooling  water  enters 
the  receiver  at  C  and  is  discharged  at  D.  The  gauge  F 
shows  the  pressure  of  the  air,  and  //  is  a  safety  valve  which 
regulates  the  pressure. 


RAILROAD  CONSTRUCTION. 

(CONTINUED.) 


TUNNEL   WORK. 

1503.  Tunnels. — The  location  and  construction  of 
tunnels  are  so  intimately  connected  that  it  has  seemed  best 
to  consider  them  under  the  head  of  construction  alone. 

When  grading  requires  a  cutting  to  exceed  60  feet,  it  be- 
comes expedient  to  drive  a  tunnel.  Tunnels  should,  when 
possible,  be  driven  on  straight  lines,  especially  for  single- 
track  roads,  in  order  to  reduce  the  danger  of  collisions. 

1504.  Laying  Out  the  Surface  Line. — The  first 
work  of  the  engineer  in  preparing  for  tunnel  work  is  to  lay 
out  the  tunnel  line  on  the  surface  of  the  ground.  If  the 
tunnel  line  is  a  tangent,  it  should  be  run  in  by  foresights,  so 
far  as  possible,  in  order  to  obviate  those  errors  due  to  defects 
in  the  adjustment  of  the  transit,  and  the  work  repeated  a 
sufficient  number  of  times  to  insure  a  true  line.  As  a  per- 
fect line  is  of  the  utmost  importance,  great  pains  should  be 
taken,  and  considerable  expense  may  be  incurred  in  securing 
long  sights.  Special  transits,  called  /wwwr/ transits,  of  double 
the  weight  and  power  of  ordinary  instruments,  are  used  in 
running  the  lines.  Frequently,  platforms  of  either  timber 
or  masonry,  several  feet  in  height,  are  erected  at  the  suc- 
cessive points  on  the  line,  their  elevation  admitting  of  much 
longer  and  clearer  sights.  The  hours  of  the  early  morning 
are  the  most  favorable  time  for  running  the  test  line."  The 
air  is  then  of  uniform  temperature,  and  the  rays  of  the  sun  so 
low  as  not  to  interfere  with  sights.  It  is  useless  to  attempt 
work  of  this  kind  when  the  wind  is  blowing.  A  cool,  cloudy 
morning  is  the  best  time,  and  in  most  situations  it  may  be 


93G 


RAILROAD   CONSTRUCTION. 


O^  had  by  watching  one's  chances. 
Some  engineers  prefer  to  run 
the  surface  Hne  (if  it  is  one  con- 
tinuous tangent)  at  night,  using 
plummet  lamps  for  sights.  The 
center  line  of  the  Cascade  tun- 
nel, on  the  Northern  Pacific 
Railroad,  was  run  in  this  way. 
The  laying,  out  of  the  surface 
line  is  illustrated  in  Fig.  423. 

Let  E  B  C  G  represent  the 
profile  of  the  hill  or  mountain 
to  be  tunneled.  Setting  up  the 
instrument  at  A  and  foresight- 
ing  to  E^  a  point  is  set  at  i?, 
the  highest  point  on  the  surface 
line  which  can  be  seen  from  A. 
Intermediate  points  H,  P,  and 

1  /fare  also  set  ivomA.    Moving 

2  the  instrument  to  B,  a  backsight 
is  taken  to  A  and  a  second 
principal  point  set  at  C,  an  in- 
termediate point  being  at  L. 
Removing  the  instrument  to  C, 
a  backsight  is  taken  to  B,  an 
intermediate  point  set  at  Q,  and 
a  fourth  principal  p©int-"Bet-«rt- 
D  in  the  opposite  tunnel  ap- 
proach. Intermediate  points 
AT,  N,  and  O  are  also  set  from 
C.  This  surface  line  may  be 
from  2,000  to  10,000  feet  in 
length,  and  yet  not  have  more 
than  half  a  dozen  intermediate 
points.  Frequently  the  surface 
is  so  broken  as  to  require  more. 
The  instruments  require  the 
most  careful  and  repeated  ad- 


RAILROAD   CONSTRUCTION. 


037 


justments.  Mountainous  country  is  especially  favorable  for 
making  careful  adjustments,  on  account  of  the  long  sights 
which  are  easily  obtained  in  such  localities.  Substantial 
monuments  should  be  set  at  each  of  the  principal  points.  A 
short  section  of  log,  cut  off  square,  or  a  section  of  sawed  tim- 
ber of  equal  length,  set  on  end  in  a  pit  and  bedded  in  cement 
mortar  rubble,  answers  this  purpose  well.  The  timber  should 
extend  three  inches  above  the  surface  of  the  ground. 

On  each  monument  two  points  are  set  about  four  inches 
apart.  At  one  of  these  points  a  vertical  hole  one  inch  in 
diameter  by  six  inches  in  depth  is  bored  to  hold  the  per- 


Fig.  424. 

manent  target,  which  is  set  up  at  each  of  the  principal  points. 
A  monument  corresponding  with  the  above  description  is 
shown  in  Fig.  424,  and  target  in  Fig.  425. 

The  target  is  made  of  pine  or  spruce.  The  shank  which 
fits  the  hole  in  the  monument  and  the  target  are  of  one 
piece.  The  surface  of  the  target  is  divided  as  shown  in  Fig. 
425,  the  inner  figures  painted  either  red  or  black  and  the 
outer  figures  white.  The  target  is  set  up  plumb,  the  points 
of  the  squares  of  different  colors  uniting  in  a  vertical  line 
which  coincides  with  the  established  center  line  denoted  in 
both  figures  by  the  letters  C  L.  Such  a  target  can  be  readily 
distinguished  with  a  good  instrument  at  a  distance  of  one 
mile,  and  is  easily  and  cheaply  made. 


938  RAILROAD   CONSTRUCTION, 

1505.  Measuring  the  Line. — After  the  line  is  estab- 
lished, it  is  measured,  a  work  requiring  great  care  and  re- 
peated checking.  Either  of  the  following  methods  may  be 
used  to  obtain  horizontal  or  true  measurement:  The  first 
method  is  by  the  use  of  a  steel  tape,  plumb-bobs,  and  spring 
balance,  in  which  the  tape  is  held  in  a  horizontal  position 
and  strained  to  the  same  tension  at  each  measurement,  the 
strain  being  measured  by  a  spring  balance.  There  will  be, 
of  course,  no  uniformity  in  the  length  of  the  sections  of  line 
measured,  the  varying  lengths  depending  mainly  upon  the 
degree  of  the  slope.  Before  the  measuring  is  commenced, 
stakes  are  firmly  set  on  line  at  such  distances  apart  as  will 
permit  easy  plumbing.  A  100-foot  standard  tape  is  used, 
unless  the  sections  are  very  short,  when  a  50-foot  tape  is 
used.  Tacks  with  small  heads  are  set  on  line  in  each  stake. 
In  measuring,  an  allowance  of  .0000066  part  of  the  length 
per  degree  is  made  for  expansion  or  contraction,  according  as 
the  temperature  at  the  time  of  measurement  is  above  or 
below  the  normal  temperature,  which  will  of  course  vary 
in  different  latitudes. 

Example. — If  a  temperature  of  50°  is  assumed  as  normal  and  at  a 
temperature  of  90°  a  line  measures  72.421  feet,  what  is  its  normal 
length  ? 

Solution.— 90°  -  50°  =  40°.  40  x  .0000066  (the  rate  of  expansion 
per  degree)  =  .000264,  the  amount  of  expansion  for  each  unit  of  length 
of  line.  The  line  measures  72.421  feet.  The  total  expansion  will, 
therefore,  be  .000264  X  72.421  =-  .019  ft.  72.421  ft.  M-.019  ft.  =  72.440,  the 
normal  length  of  the  line. 

For  measurements  of  100  feet  or  less  a  tension  of  16  pounds 
is  sufficient.  This  process  of  measuring  is  illustrated  in 
Fig.  426. 

The  head  tapeman  holds  the  zero  end  of  the  tape  with  the 
spring  balance  attached  at  B. 

The  hind  tapeman,  standing  at  A,  holds  the  tape  above 
the  stake  until  it  is  in  a  horizontal  position.  The  tape 
carries  a  rider  containing  a  spirit  level  and  a  small  eye 
through  which  the  plumb-bob  cord  is  passed.  There  are 
two  rear  tapemen.     One   holds  the  tape  and  gives  it  the 


RAILROAD   CONSTRUCTION. 


939 


requisite  tension,  which  is  reported  by  the  head  tapeman  at 
B\  the  other  directs  the  raising  or  lowering  of  the  tape  while 
bringing  it  into  a  horizontal  position,  adjusts  the  plumb- 


bob,  and  reads  the  tape.  The  reading  is  then  recorded. 
The  rear  tapemen  then  change  places  and  repeat  the  work 
and  record  the  measurements.     Each  man  must  read  and 


^ 


""' '" 


liiiili 


i 


a|iMiliii^iiiiliiii|ft 


®c 


rliiiTliiiiljiiir    \ 


E 


Fig.  427. 


record  his  measurements  independently  of  the  other,  in  order 
that  they  may  the  better  check  each  other's  work.  Accord- 
ingly they  do  not  call  out  the  measurements,  but  after  each 


940  RAILROAD    CONSTRUCTION. 

has  read  and  recorded  his  measurements,  they  compare 
results,  and  if  there  is  any  considerable  discrepancy,  the  work 
must  be  repeated. 

Fig.  427  shows  form  of  tape  rider  for  plumbing  tape.  It 
consists  of  a  piece  of  sheet  brass  A  B,  6  inches  in  length,  an 
end  view  being  shown  at  C.  It  is  bent  so  as  to  fit  closely 
to  the  sides  and  top  of  the  tape  when  stretched,  and  slides 
along  the  tape.  An  open  slot  a  d,  2  inches  in  length,  in  the 
side  of  the  rider  shows  the  graduationson  the  tape.  A  spirit 
level  D  £  is  attached  to  the  under  side  of  the  rider.  To 
the  under  side  of  the  bubble  tube  at  its  middle  point  an  eye 
c  is  attached,  from  which  the  plumb-bob  /^  is  suspended. 
Directly  over  this  eye  and  fastened  to  the  rider  is  a  fine 
point  ^,  which  indicates  to  the  tapemen  the  precise  reading 
of  the  tape. 

The  second  method  of  measuring  is  as  follows:  The 
stakes  are  driven  as  in  the  first  method,  and  the  slope  meas- 
urements from  center  of  tack  to  center  of  tack  are  taken, 
the  spring  balance  used,  and  allowance  for  expansion  or 
contraction  made  as  in  the  first  method.  The  levels  are 
then  taken  between  the  different  stakes,  the  tack  in  the  top  of 
each  stake  being  taken  instead  of  the  surface  of  the  ground, 
and  the  slope  distances  are  then  reduced  to  horizontal  dis- 
tances.    This  method  is  illustrated  in  Fig.  428. 

The  distance  a  b  measured  on  the  slope  is  68.10  feet, 
^^  =  75.111  feet,  ^Trt'^z  57.166  feet.  The  difference  in  ele- 
vation between  a  and  b  \%  a  a'  ■=  10.811 ;  between  b  and  c  is 
(^(^'  =  20.42  feet;  between  c  and  d  is  rr'  =  20.752  feet. 
aa'  b  forms  a  right-angled  triangle,  right  angled  at  a\  in 
which  the  hypotenuse  is  the  slope  distance,  68.10  feet,  and 
the  altitude  a  a'  is  the  difference  in  elevation  between  a 
and  ^=16.811  feet.      From  the   trigonometrical    formula 

side  opposite  ,  ■  u     <      16.811        nAaop 

sm  = -, i-5- ,    we    have    sm   a  o  a  =^  —r;7r^r-  =  .24686, 

hypotenuse  08.1 

whence  angle  a  ba'  =  14°  17'.  The  base  a'  b,  which  is  the 
horizontal  distance  between  a  and  b,  is  obtained  by  apply- 
ing  the  formula   tan  a  b  a'  =  -^ f^ .      Substituting 

side  adjacent 


RAILROAD   CONSTRUCTION. 


941 


known 

have  tan  14°  17'  = 


quantities,      we 
10.811 


.16.811 


a'  b 
1G.811 


whence  a!  b  —    ,..,.^ 

6G.  032  feet.  By  a  similar 
process  we  determine  the 
length  of  b'  c,  and  find 
that  it  equals  72.242  feet, 
and  that  c'  d  =  53.272 
feet.  The  total  horizon- 
tal distance  between  a 
and  d  is  the  sum  of 
a' b-{-b'c-\-c'd  =  191.54:6 
feet.  This  method  of 
measurement  is  possible 
where  the  slopes  are  so 
abrupt  as  to  render  the  ^  1 
use  of  the  plumb-bob  P  J$ 
practically  impossible.        ^  ^ 


1506.  Stationing. 

— Stations  are  estab- 
lished at  each  50  feet,  and 
if  the  surface  be  very 
rough,  at  each  25  feet,  in 
order  that  a  correct  pro- 
file of  the  surface  may  be 
obtained. 

1507.  Curved  Tun- 
nel Lines. — When  the 
tunnel  line  is  curved,  the 
tangents  are  made  to 
intersect,  if  possible,  and 
the  angle  of  intersection 
is    measured    with     the 


942 


RAILROAD   CONSTRUCTION. 


transit.  The  tangent  distances  are  calculated  and  the  P.  C. 
and  P.  T.  located  by  direct  measurement.  The  work  and 
calculations  are  repeated  many  times,  and  every  possible 
precaution   taken   to   secure   perfect   accuracy   of    results. 


Orad&H-0. 75 


Fig.  430. 


The  sketch  given  in  Fig.  429  shows  the  difficulties  attending 
the  laying  out  of  the  Rockport  tunnel  on  the  Lehigh  Valley 
Railroad.        • 

The  original  line  A  B  C  D  followed  the  course  of  the 
Lehigh  river,  which  hugs  the  bluff  E.  The  tunnel  line 
A  F  G  H  \iov\di  have  been  adopted  and  the  tunnel  driven 
when  the  road  was  first  constructed,  but  a  rival  line  was 
building  on  the  opposite  side  of  the  river,  and  there  was  a 


RAILROAD   CONSTRUCTION.  943 

race  to  reach  the  Wyoming  Valley  coal  fields  and  command 
the  coal  traffic.  The  tunnel  line  was  accordingly  postponed 
and  the  river  line  adopted.  After  a  lapse  of  twenty  years 
the  tunnel  was  driven  in  1882-3.  The  neck  F  G  through 
which  the  tunnel  passes  (a  profile  of  which  is  shown  in  Fig. 
430)  reached  a  height  of  more  than  300  feet.  The  hillsides 
were  so  steep  that  in  places  a  man  could  hardly  stand.  The 
tangent  K  F  \s  the  prolongation  of  the  original  tangent  A  K. 
The  grade  of  the  original  line  was  about  20  feet  per  mile, 
and  as  there  was  a  gain  in  distance  of  nearly  1^  miles,  there 
resulted  a  discrepancy  in  grades  at  L  of  about  30  feet.  In 
order  to  dispose  of  this  difference,  the  grade  on  the  old 
tangent  A  K  and  on  the  tunnel  curve  was  increased  to 
40  feet  per  mile.  In  place  of  the  original  tangent  L  D,  the 
tangent  G  H  was  substituted,  and  z.'a  G  H  has  a  grade  of 
40  feet  per  mile  against  L  D  oi  20  feet,  it  will  be  seen  that 
the  two  grade  lines  constantly  approach  each  other.  The 
difference  in  grade  being  30  feet,  it  required,  at  a  gain  in 
grade  of  20  feet  per  mile,  a  distance  of  1^  miles  for  the  two 
grades  to  meet.  The  tangents  A  K  and  G  H  being  estab- 
lished, they  were  produced  intersecting  at  M.  The  inter- 
section angle  G  M  N  measured  57°.  A  5°  18'  curve  was 
decided  upon,  and  the  tangent  distances  M  F  and  M  G 
measured  by  direct  measurement,  and  the  P.  C.  and  P.  T. 
set. 

On  account  of  the  steepness  of  the  slopes  and  the  height 
of  the  hill,  much  difficulty  was  experienced  in  making  a 
satisfactory  intersection.  Within  a  distance  of  500  feet 
there  was  a  difference  in  elevation  of  more  than  300  feet,  and, 
though  taking  every  precaution,  some  of  the  sights  contained 
a  vertical  angle  of  more  than  60°.  The  lines  were  run 
principally  in  the  early  morning  hours,  though  some  of  the 
best  results  were  obtained  on  cloudy  days.  A  large  tunnel 
transit  with  powerful  lenses,  and  of  more  than  double  the 
weight  of  an  ordinary  transit,  was  used.  Common  pins 
against  a  dark  background  were  used  for  backsights.  First 
an  intersection  was  made,  large  plugs  (6  inches  square) 
being  used.     The  tangent  K  M  was  then  repeatedly  run, 


944  RAILROAD   CONSTRUCTION. 

and  each  line  marked  on  the  plugs  O  and  P,  Fig.  431,  with 
tacks,  each  one  of  which  was  numbered,  as  shown  in  the 
figure.  The  lines  varied  each  time,  no  two  coinciding. 
One  or  two  fell  wide  of  the  mark  and  were  ignored.  Finally 
the  mean  of  the  lines  (as  shown  by  the  heavy  line  in  the 
figure)   was  adopted  as  final.     The  tangent  G  M  was  then 


Fig.  431.  Fig.  43a. 

run  an  equal  number  of  times,  and  each  intersection  on  the 
line  O'  P' ,  Fig.  432,  marked  on  the  plug  Q'  with  a  tack  and 
numbered.  The  mean  of  these  intersections,  as  indicated 
by  the  heavy  line,  was  taken  as  final. 

Equally  great  difficulty  was  experienced  in  locating  the 
P.  C.  and  P.  T.  The  distance  was  measured  many  times, 
and  each  distance  marked.  The  mean  was  then  taken  as 
the  correct  measurement.  The  top  of  the  hill  had  the  form 
of  a  plateau,  and  the  center  of  the  curve,  O,  was  located  by 
turning  a  right  angle  to  the  tangent  A' F  at  .F,  the  P.  C, 
and  measuring  the  radius  1,081.44  feet,  locating  the  center 
O.  The  central  angle  F  O  G  oi  57°  was  then  turned,  and 
the  second  radius  O  G  run  out  and  measured.  The  line  and 
measurement  falling  on  the  plug  at  the  P.  T.  at  G  proved 
the  work  correct.  The  reward  for  all  this  care  and  pains 
was  in  the  almost  perfect  alinement  of  the  tunnel.  The 
tunnel  was  driven  from  both  ends,  and  when  the  headings 
met  there  was  found  to  be  less  than  a  half  inch  discrepancy 
in  the  two  lines. 

1508.  Tunnel  Sections. — Tunnel  sections  vary 
somewhat,  according  to  the  material  to  be  excavated,  but 
the  general  form  and  dimensions  are  much  the  same. 


RAILROAD   CONSTRUCTION. 


945 


The  general  dimensions  are  as  follows  :  For  double  track 
from  22  to  27  feet  wide  and  from  21  to  24  feet  high,  and 


Section  of  Double  Track  Ttinnel. 


Section  of  Sin-^'.r  Trn-'k  Tunnel. 


Fig.  433. 


Fig.  4.34. 


for  single  track  from   14  to  10  feet  wide  and  from  17  to  20 
feet  high.      See  Figs.  4;3o  and  434. 

In  seamy  or  rotten  rock  the  section  is  sufficiently  enlarged 
to  receive  a  lining  of  substantial  rubble  or  brick  masonry 
laid  in  good  cement  mortar.  When  the  material  has  not 
sufficient  consistency  to  sustain  itself  until  the  masonry 
lining  is  built,  resort  is  had  to  timbering,  which  furnishes  the 
necessary  support. 

1509.  Tunnel  Driving. — Tunnels  in  rock  are  driven 
either  by  hand  or  machine  drills.  The  requirements  of 
modern  railroad  construction  are  such  that  hand  drills  play 
a  very  important  part  in  tunnel  work.  There  are  many 
points  in  favor  of  hand  drills  and  hammers,  viz.,  portability, 
cheapness,  and  immunity  from  the  accidents  which  fre- 
quently cause  delays  where  machine  drills  are  used.  But 
the  process  is  slow,  compared  with  machine  work,  and  time 
limitations  have  made  the  use  of  machine  drills  compulsory. 

1510.  Plant. — The  plant  for  furnishing  the  com- 
pressed air  used  in  working  the  drills  consists  of  a  boiler 
house    where    steam    is    generated,    and    an   engine   house 


946  RAILROAD    CONSTRUCTION. 

containing  the  engines,  air  compressor,  and  air  receiver.  Both 
houses  are  usually  under  one  roof.  If  the  tunnel  is  short,  a 
single  plant,  situated  near  one  of  the  tunnel  portals,  furnishes 
power  for  all  the  machinery  used  at  both  working  faces. 
When  the  tunnel  is  of  great  length,  an  air  compressing  plant 
is  stationed  at  both  ends.  About  12  horsepower  is  required 
to  run  each  drill  (drill  cylinders  3i  to  3^  inches  in  diameter), 
and  as  each  tunnel  face  requires  six  drills,  a  70-horsepower 
boiler  and  engine  is  required  to  work  each  tunnel  face. 
When  the  air  is  conveyed  a  great  distance,  there  is  some 
loss  of  power  through  friction.  A  three-inch  pipe  will  carry 
sufficient  air  for  six  drills.  The  pipe  couplings  are  well  leaded 
to  prevent  waste  of  air. 

1511.  Method  of  Driving. — When  the  material  is 
rock,  the  mode  of  driving  is  the  following  :  The  tunnel  sec- 
tion is  divided  into  two  parts,  viz.,  the  heading  and  the 
bench.  The  heading  comprises  from  one-fifth  to  one-fourth 
of  the  entire  section  extending  from  the  roof  downward.  It 
is  from  G  to  8  feet  in  height,  and  is  kept  from  50  to  250  feet 
in  advance  of  the  remainder  of  the  section,  which  is  the 
bench.  The  drills  working  in  the  heading  are  mounted 
upon  columns,  two  drills  on  each  column.  The  drills  work- 
ing on  the  bench  are  mounted  upon  tripods.  The  air  pipe 
is  carried  to  within  about  50  feet  of  the  bench,  where  a  bench 
hose  of  equal  diameter  is  attached  to  the  air  pipe,  lead- 
ing directly  to  the  bench.  At  the  end  of  the  hose  is  a  metal 
nozzle  called  a  manifold,  containing  hose  connections  for 
each  of  the  drills. 

A  section  of  heading  showing  arrangement  of  drill  holes 
in  the  face  is  given  in  Fig.  435.  The  two  middle  rows  of 
holes  A  B  and  CD  converge  at  an  angle  of  about  20°, 
nearly  meeting  on  the  center  line  E  F  oi  the  tunnel,  and  are 
called  the  center  cut  holes.  The  mass  of  rock  included 
by  these  holes  is  wedge-shaped  and  shown  in  plan  at  A  in 
Fig.  43G.  The  removing  of  this  wedge  by  blasting  i«j  called 
breaking  the  cut.  Fig.  437  shows  a  longitudinal  section 
through  the  center  cut  holes.     The  rows  of  holes  G,  H,  A', 


RAILROAD   CONSTRUCTION. 


947 


and  Z,  Fig.  435,  on  each  side  of  the  center  cut  holes,  are 
called  side  rounds.     If  but  one  row  on  each  side,  they  are 


Fig.  435. 


Fig.  437. 


Fig.  436. 


Pig.  438. 


called   single   side   rounds ;  if  two   rows,  double   side 
rounds.     A  longitudinal  section  through  the  side  holes  is 


Fig.  439. 


Fig.  440. 


Fig.  441. 


FlO.442. 


given  in  Fig.  438.     The  cut  and  side  rounds  are  loaded  at 
the  same  time.     'I^he  cut  is  fired  first  (see  Fig.  439),  followed 


948 


RAILROAD   CONSTRUCTION. 


by  the  side  rounds,  which  are  fired  either  single,  i.e.,  one 
row  on  each  side  of  the  cut  (see  Figs.  440  and  441),  or 
double  fired,  i.  e.,  both  rows  fired  simultaneously,  as  shown 
in  Fig.  442. 

1512.  Enlarging  the  Heading. — In  that  portion  of 
the  heading  shown  in  the  preceding  figures,  the  holes  are 
drilled  directly  into  the  face  of  the  heading.  After  the 
holes   are   fired   and  the  material  removed,  side  holes  are 


Fig.  444. 


Fig.  445. 


drilled  at  an  angle  of  about  60°  with  the  center  line  denoted 
by  the  letters  C.  Z.,  as  shown  in  section  in  Fig.  443  and* 
plan  in  Fig.  444. 

1513-  Removing  the  Bench. — The  bench  is  taken 
out  in  two  sections,  B  and  />',  as  shown  in  section  in  Fig. 
445.     The  full  tunnel  section  is  shown  by  dotted  lines. 

The  holes  in  the  bench  are  inclined  backward  from  a  ver- 
tical line.  A  longitudinal  section  through  the  center  line, 
showing  the  usual  mode  of  drilling  headings  and  benches,  is 
given  in  Fig.  440.  The  center  cut  holes  in  the  heading  // 
and  all  the  bench    holes    at    B    and    B'  are    usually   fired 


RAILROAD   CONSTRUCTION.  949 

together,  followed  by  double  side  rounds  in  the  heading. 
The  center  cut  offers  the  greatest  resistance  to  blasting. 
The  holes  are  consequently  loaded  with  more  powerful 
explosives  than  are  used  for  either  side  rounds  or  bench. 

In  driving  the  New  York  aqueduct  tunnel,  the  cut  was 
loaded  with  dynamite  containing  from  GO  to  80  per  cent,  of 
hitro-glycerine,  while  the  average  bench  powder  contained 
but  40  per  cent,  of  nitro-glycerine.  On  some  sections, 
where  rock  of  special  hardness  was  encountered,  the  cut 
was   loaded  with    pure    nitro-glycerine.     This  operation  is 


.^;^-.^-~^^ 


Fig.  446. 

always  attended  with  great  danger.  After  several  prema- 
ture explosions,  resulting  in  considerable  loss  of  life,  the  use 
of  pure  nitro-glycerine  was  abandoned.  The  effect  of  firing 
the  cut  is  generally  to  pulverize  the  rock,  and  all  tunnel 
blasting  is  intended  to  so  break  the  rock  as  to  render  the  use 
of  the  sledge-hammer  unnecessary  in  reducing  masses  of 
rock  to  sizes  convenient  for  loading. 

The  execution  of  the  powder  depends  largely  upon  the 
judgment  used  in  locating  the  holes  and  the  angle  at  which 
they  are  bored.  The  position  of  the  machine  while  drilling 
holes  at  foot  of  the  bench  is  shown  at  C,  Fig.  446. 


950  RAILROAD   CONSTRUCTION. 

1514.  Drainage. — The  grade  of  a  tunnel  must  be 
established  with  reference  to  securing  complete  drainage. 
When  the  grade  at  both  portals  is  the  same,  the  grade  of  the 
tunnel  is  made  to  ascend  from  both  ends,  the  grades  being 
united  by  a  flat  vertical  curve.  The  grade  of  the  St.  Goth- 
ard  tunnel  is  0.1  per  cent. ;  that  of  Mt.  Cenis  0.05  per  cent., 
but  these  grades  are  very  light.  A  grade  of  0.25  per  cent, 
will  insure  complete  drainage  and  need  not  be  exceeded.  If 
the  tunnel  is  short,  a  continuous  grade  may  be  employed. 
In  such  a  case,  if  the  tunnel  is  driven  from  both  ends,  it  will 
be  necessary  to  remove  the  water  from  the  descending  por- 
tion by  pumping.  In  tunnels  of  considerable  length,  the 
grade  is  usually  made  to  ascend  from  both  ends.  This  pro- 
vides complete  drainage  during  construction  and  also  i  educes 
the  cost  of  removing  the  excavated  material,  as  the  loaded 
cars  will  either  run  of  themselves  or  with  small  draft. 
When  shafts  are  sunk,  the  water  is  removed  frorn  the  tunnel 
by  pumping. 

1515.  Shafting. — When  the  tunnel  is  of  considerable 
length,  and  dispatch  in  driving  is  of  great  importance,  ad- 
ditional working  faces  are  obtained  by  sinking  one  or  more 
shafts,  each  shaft  affording  two  additional  working  faces. 
Shafting  adds  very  considerably  to  ^the  cost  of  tunnel  dri- 
ving; for,  besides  the  cost  of  sinking  the  shaft,  there  is  the 
constant  expense  of  hoisting  the  excava:ed  material  to  the 
surface,  to  which  must  be  added  the  expense  of  pumping. 
On  the  New  York  aqueduct  tunnel,  which  has  a  total  length 
of  about  33  miles,  a  shaft  was  sunk  at  each  interval  of  one 
mile,  the  shafts  varying  in  depth  from  80  to  380  feet.  Where 
shafts  are  employed,  the  greatest  care  and  skill  are  neces- 
sary in  transferring  the  alinement  from  the  surface  of  the 
ground  to  the  tvmnel  at  the  foot  of  the  shaft. 

1516.  Shaft  Lining. — When  the  shaft  is  sunk  through 
solid  rock,  the  walls  are  self  sustaining,  and  no  timber  lining  is 
required  except  a  curb  at  the  top  of  the  shaft.  If,  however, 
the  material  is  earth,  loose  rock,  or  shale,  the  shaft  must  be 
timbered.     The  timbers  are  put  in  place  as  the  shaft  is  sunk. 


RAILROAD   CONSTRUCTION. 


951 


Frames  {se/s,  they  are  commonly  called)  of  timber,  shown 
at  A  in  Fig.  447,  are  placed  about  4  feet  apart,  and  behind 
these  frames,  lagging^,  of  either  sawed  timber  or  half  round 
poles  split  from  young  trees,  is  placed  on  end  and  in  close 
contact.  As  each  frame  is  placed  in  position  it  is  supported 
by  struts  footing  on  the  bottom  of  the  shaft,  or  if  the  walls 
are  sufficiently  firm,  the  frames  are  held  in  place  by  wedges, 


Fig.  447. 


until  another  set  is  required,  when  timber  struts  C,  mortised 
into  the  frames,  form  the  permanent  support.  These  struts 
are  placed  one  above  the  other,  and,  together  with  the 
frames  into  which  they  are  mortised,  form  continuous  tim- 
ber columns  extending  from  the  bottom  to  the  top  of  the 
shaft.  With  each  set  of  timbers  a  horizontal  timber  D, 
called  a  bunton,  is  placed  with  ends  abutting  against  the 


952  RAILROAD   CONSTRUCTION. 

vertical  timber  E.  A  beveled  seat  with  a  square  shoulder 
is  cut  on  the  vertical  timber  for  each  bunton.  The  buntons 
are  held  in  place  by  wedges  shown  at  /^and  F' .  These 
wedges  are  forced  between  the  bunton  and  the  shoulder  of 
the  beveled  seat.  As  the  wedges  are  tightened,  the  bunton 
is  forced  downwards  until  it  is  perfectly  rigid.  Vertical  tim- 
bers 6",  G'  are  spiked  to  the  buntons  and  to  the  ends  of  the 
frames,  to  serve  as  guides  for  the  carriage.  A  detail  of  the 
splice  of  the  carriage  guide  is  shown  at  H  and  of  the  wedges 
at  K.  As  all  shafts  are  moist,  and  many  decidedly  wet, 
iron  should  only  be  used  in  timbering  when  no  substitute 
can  be  found.  The  pressure  of  earth  or  loose  rock  against 
the  timbers  is  usually  sufficient  to  hold  them  in  place,  and 
most  of  the  joints  do  not  require  keying.  Treenails 
(wooden  pins)  should  be  used  in  place  of  iron.  The  lagging 
must  be  put  in  place  as  fast  as  the  work  progresses,  and  all 
spaces  behind  it  filled  with  welUrammed  earth.  In  very 
wet  ground  or  in  quicksand,  special  devices  are  employed 
to  meet  the  needs  of  the  situation.  Shaft  sinking  in  bad 
ground  is  exceedingly  dangerous  work,  and  every  known 
precaution  is  essential  if  loss  of  life  would  be  avoided. 

1517.  Removing  Excavated  Material.  — The  ma- 
terial excavated  in  tunnel  driving  is  called  muck.  The 
muck  is  loaded  into  dump  cars  at  the  foot  of  the  bench, 
which,  when  there  is  a  sufficient  descending  grade,  run  by 
gravity  either  to  the  foot  of  the  shaft,  where  they  are  hoisted 
to  the  surface,  or  to  the  dump  outside  the  tunnel.  When 
there  is  not  sufficient  grade  to  run  the  cars  of  themselves, 
mules  are  employed  to  haul  them. 

A  single  track  A^  Fig.  448  (ordinarily  of  3  feet  gauge),  is 
laid  on  the  center  line  of  the  tunnel,  with  passing  branches 
at  suitable  intervals.  At  a  distance  of  about  100  feet  from 
the  bench  a  simple  switch  is  built,  and  two  tracks  C  and  D 
laid  to  the  bench,  which  permit  the  loading  of  two  cars  at 
the  same  time,  and  provide  for  shifting  cars.  On  a  level 
with  the  top  of  the  bench,  and  directly  over  the  cars,  a  scaf- 
fold E  is  erected,  and  upon  it  a  runway  of  planks  F  is  laid. 


RAILROAD   CONSTRUCTION. 


953 


extending  from  the  scaffold  to  the  heading.  The  heading 
muck  is  loaded  into  barrows  and  wheeled  on  this  runway  to 
the  scaffold,  and  emptied  directly  into  the  cars. 

A  simple  and  very  effective  bench  scaffold  is  made  of 
wrought  iron  pipe  supports  and  shown  in  Fig.  448.  Each 
support  consists  of  two  pieces  of  pipe,  one  telescoping  within 


v^?^^-*/y///y////riu/////////Znc////^////////)i^////////ZZ'iii,'^//^^^ 


¥^- 


.,-C^.JRsx 


"---■Jiitb  ifrajic.     -^ 

Fig.  448. 

the  Other,  and  provided  with  clamps  by  means  of  which 
they  are  adjusted  to  any  desired  length.  The  plank  is  laid 
directly  upon  these  pipe  supports.  The  air  for  working  the 
drills  is  carried  from  the  air  pipe  G  to  the  bench  by  means 
of  the  bench  hose  //.  The  manifold  K  attached  to  the  end 
of  the  bench  hose  contains  hose  connections  for  all  the  drills. 
A  ditch  L  on  the  opposite  side  of  tunnel  from  the  air  pipe 
drains  the  tunnel. 


954 


RAILROAD   CONSTRUCTION. 


3      5 


As  the  work  advances  from  the  tunnel  entrance,  or  from 
the  foot  of  the  shaft,  more  time  is  required  to  haul  away 
the  loaded  cars  and  bring  back  the 
empty  ones.  When  one  mule  is  no 
longer  able  to  perform  the  work  a 
second  one  is  added,  and  passing 
branches  are  built  in  the  main  track 
at  suitable  intervals,  where  returning 
empty  cars  are  switched  while  the 
loaded  cars  are  passing  outward.  A 
passing  branch  contains  two  switches, 
which  are  made  self-acting  by  the 
following  simple  device,  shown  in 
Fig.  449.  The  points  of  the  switch 
rails  a  and  b  are  connected  by  a 
clamp  rod,  attached  to  a  spring  c  d, 
which  is  constantly  acting,  and  holds 
the  point  a  close  against  the  main 
rail  c  f,  and  the  switch  is  constantly 
set  for  the  passing  branch  k  I.  The 
switch  points  ;;/  and  fi  of  the  second 
switch  are  kept  in  place  by  the  spring 
op,  the  switch  being  always  set  for 
the  main  track  q  r.  An  outgoing 
car  running  in  the  direction  r  q  finds 
the  switch  Y  set  for  the  main  track. 
Upon  reaching  the  switch  X,  the 
flange  of  the  right-hand  wheel,  pass- 
ing between  the  rail  e  f  and  the 
switch  point  a,  forces  the  switch 
point  b  against  the  rail  s  /,  and  the 
car  passes  the  switch  in  safety.  A 
returning  empty  car  finds  the  switch 
X  set  for  the  passing  branch  k  /,  and  in  passing  from  the 
branch  to  the  main  track,  the  flange  of  the  head  wheel,  in 
passing  between  the  rail  u  t  and  the  switch  point  ;//,  forces 
the  switch  point  n  against  the  main  rail  c  f,  and  the  car 
passes  safely  on  to  the  main  track.     The  springs  c  ^and  op 


RAILROAD   CONSTRUCTION.  955 

are  elastic  young  saplings,  kept  in  place  by  strong  staples 
driven  into  the  switch  ties. 

151S.  Care  of  Track. — A  common  fault  of  contract- 
ors and  their  employes  is  neglect  of  track.  Usually  poor 
material  is  furnished,  worn  cut  and  crooked  rails,  poor 
fastenings,  poor  ties,  and  often  no  ties,  requiring  every 
sort  of  makeshift.  With  such  material  a  good  track  is  im- 
possible, and  requires  constant  tinkering.  Derailments  are 
continually  occurring,  involving  costly  delays.  Tunnel 
tracks  should  be  built  of  good  material  and  in  a  thorough 
manner.  Short  rails  of  varying  lengths  are  required  in 
keeping  the  track  well  up  to  the  bench.  With  proper  care 
of  tracks,  the  cars  may  be  kept  within  easy  shoveling  dis- 
tance of  the  bench.  The  foreman  in  charge  of  the  muckers 
should  keep  a  small  stock  of  ties  and  rails  constantly  on 
hand,  together  with  the  necessary  track  tools,  and  do  his 
own  track  work. 

1519.  Keeping  Down  to  Grade. — The  invariable 
tendency  in  tunnel  work  is  to  keep  above  grade.  The  prin- 
cipal cause  is  the  unconscious  effort  to  avoid  the  water  which 
is  constantly  accumulating.  This  tendency  can  only  be 
avoided  by  establishing  grade  stakes  at  every  25  feet  and 
keeping  the  excavation  on  true  lines.  The  holes  drilled  at 
the  foot  of  the  bench  should  penetrate  a  foot  below  grade, 
which  will  insure  the  removal  of  the  entire  section.  Much 
of  the  muck  in  the  bottom  of  the  tunnel  will  require  severe 
use  of  the  pick  to  remove  it.  Wedges  and  a  heavy  sledge 
are  often  of  great  service  in  this  work. 

1520.  Timbering. — When  the  material  is  rotten  rock 
or  earth,  the  tunnel  must  be  timbered.  The  timbered  sec- 
tion should  be  enough  larger  than  the  standard  section  to 
admit  of  a  masonry  lining.  When  the  material  is  such  that 
the  side  walls  will  stand  of  themselves  for  a  time,  hitches 
A  and  B  are  excavated  near  the  springing  line  and  sets  of 
timbers  placed  as  shown  in  Fig.  450.  Iron  clamps  shown  at 
C  and  D  hold  the  timbers  together  while  the  lagging  is 


956 


RAILROAD   CONSTRUCTION. 


being  placed.     It  is  laid  over  the  timbers  lengthwise  of  the 
tunnel  and  as  close  together  as  possible.  •   The  spaces  G,  H 


[Fig.  150. 

between  the  lagging  and  the  roof  are  filled  with  dry  rubble 
or  cordwood. 

Roof  timbers  should  be  either  12  in.  X  12  in.  or  12  in. 
X  14  in.  in  cross-section,  and  placed  with  2  to  4  feet  clear 
space  between  each  set.  Where  the  ground  is  very  soft 
with  a  tendency  to  expand,  larger  timbers  may  be  necessary. 
Hemlock,  yellow  pine,  or  spruce  is  commonly  used.  In 
special  cases,  where  great  pressure  is  to  be  resisted,  oak  is 
used.  When  the  side  walls  will  not  support  the  roof  tim- 
bers, they  are  carried  on  supports  arranged  as  shown  in 
Fig.  451.  Four  posts  A,  C,  D  and  i),  resting  on  sills  O,  P,  Q 
and  Ry  are  mortised  into  the  cap  E  F. 

The  roof  timbers  G,  H,  AT  are  clamped  together  as  in  Fig. 


RAILROAD   CONSTRUCTION. 


957 


450,  and  mortised  into  the  cap  at  spring  line.  The  pressure 
against  the  roof  timbers  is  relieved  by  the  struts  Z,  J/,  N^  U, 
and  V,  which  transfer  the  stress  to  the  posts  C  and  D  and 
the  cap  E  F.  The  dimensions  of  timber  given  in  the  draw- 
ing are  such  as  are  used  where  the  pressure  is  great;  they 
will  meet  the  requirements  of  most  situations.  The  lagging 
may  be  either  sawed  timber  or  split  poles,  obtained  by  split- 


FlG.  451. 

ting  in  half  straight  grained  chestnut  or  oak  saplings.  The 
backing  may  be  either  dry  rubble  or  cordwood.  The  latter 
is  preferable,  as  it  is  light,  portable,  and  uniform  in  shape. 
The  side  walls  are  all  of  well-scabbled  rubble  of  good-sized 
stones,  even  beds,  and  laid  in  courses  with  cement  mortar. 
The  impost  courses  S  and  T  should  be  of  well-cut  stone, 
twelve  inches  in  thickness  and  of  full  width  of  wall.  The 
arch   is  either'  brick  or  rubble.     The  caps  and  roof  struts 


958 


RAILROAD   CONSTRUCTION. 


interfere  somewhat  with  arching.  Holes  are  left  in  the 
masonry  where  these  timbers  interfere  until  a  section  of  the 
arch  is  complete,  when  they  are  removed  and  the  gaps  filled 
with  masonry,  the  joints  being  thoroughly  grouted.  All 
other  timbers  are  left  in  place.  The  spaces  /f,  Z,  etc.,  Fig. 
450,  between  the  arch  and  roof  timbers,  are  usually  filled 
with  concrete. 

When  the  material  through  which  the  tunnel  passes  is 
very  soft,  with  slight  coherence,  all  the  energy  and  skill 
of  engineer  and  workmen  are  required  to  make  headway. 
It  is  considered  the  better  practice  to  drive  the  heading  at 
the  bottom  of  the  tunnel  instead  of  the  top,  as  by  the  time 


Fig.  452. 

the  heading  is  driven  the  ground  composing  the  remainder 
of  the  section  will  have  become  thoroughly  drained,  and  may 
be  taken  out  with  much  greater  safety  and  less  expense 
than  with  a  top  heading.  The  mode  of  driving  a  heading 
through  such  material  is  illustrated  in  Fig.  452,  in  which 
A  represents  a  cross-section  and  B  a  longitudinal  section  of 
the  heading,  with  complete  system  of  timbering. 

A  full  section  of  timbers  is  called  a  set^  of  which  the  up- 
right timber  C  is  called  the  leg;  the  horizontal  timber  D  the 
sill,  and  E  the  cap  or  collar.  The  short  boards  F,  F,  which 
extend  from  collar  to  collar,  and  are  in  direct  contact  with 
the  sustained  material,  are  caUed  poling- doards.  They  are 
sharpened  to  a  cutting  edge,  and  are  driven  into  the  face  of 
the  heading  with  sledges,  a  wedge-shaped  block    G  being 


RAILROAD   CONSTRUCTION.  959 

placed  above  them  to  keep  them  at  a  proper  angle.  The 
planks  H  which  protect  the  sides  of  the  heading  are  termed 
lagging.  The  flooring  K  serves  to  exclude  the  liquid  mud, 
which  would  otherwise  be  forced  from  underneath  by  the 
external  pressure.  The  horizontal  cross  timber  Z,  as  well 
as  the  longitudinal  timbers  M  and  A^,  are  called  struts.  The 
floor  O  serves  as  a  footing  for  the  workmen  while  driving 
the  poling  boards. 

If  the  material  penetrated  is  wet  enough  to  run,  it  is 
necessary  to  constantly  maintain  a  bulkhead  of  planks 
/*,  called  face  boards,  which  is  held  in  place  by  struts  Q.  As 
the  poling  boards  are  driven  forward,  the  top  face  board  is 
removed,  allowing  the  released  material  to  flow  into  the 
gangway.  This  forms  a  cavity  in  the  face  of  the  heading, 
and  immediately  another  bulkhead  is  started  by  placing  a 
face  board  R  in  advance  of  those  at  /*,  with  a  strut  5  to 
keep  it  in  place.  When  the  heading  is  advanced  half  the 
length  of  the  poling  boards,  a  new  set  of  timbers  is  put  in 
place,  the  collar  of  which  takes  the  strain  from  the  poling 
boards,  which  would  otherwise  be  soon  broken  by  the  great 
pressure  above  them. 

As  the  section  is  enlarged,  other  timbers  are  substituted, 
until  the  complete  section  is  excavated.  The  masonry 
lining  should  follow  immediately.  The  less  important  tim- 
bers may  be  removed  as  the  masonry  advances,  and  their 
stresses  transferred  to  it;  but  the  main  supports  should  re- 
main in  place,  and  the  masonry  be  built  around  them,  and 
not  disturbed  until  the  arch  is  keyed.  They  can  then  be 
removed  with  safety,  and  the  vacancies  in  the  masonry 
carefully  filled  and  grouted.  All  open  spaces  between  the 
masonry  and  the  timber  should  be  filled  with  well-rammed 
concrete. 

1 521 .  Centering.  — Tunnel  centers  are  built  on  much 
the  same  plan  as  those  used  in  arched  culverts,  a  full 
description  of  which  was  given  in  Arts.  1475  and  1476. 

1522.  Portals. — Tunnel  portals  correspond  to  the 
face  and  wing  walls  of  an  arched  culvert.     Usually  some 


9G0  RAILROAD   CONSTRUCTION. 

regard  is  paid  to  architectural  effect,   the  walls  being  of 
dressed  stone  laid  in  courses. 

1523.  Alinement  and  Levels. — During  construc- 
tion, the  alinement  and  levels  must  be  frequently  tested. 
At  least  once  a  week  the  heading  should  be  carefully 
centered,  and  a  grade  stake  set  at  the  foot  of  the  bench. 

In  running  the  center  line,  plummet  lamps  are  used  in- 
stead of  the  transit  poles  used  on  surface  lines.  A  plummet 
lamp  consists  of  an  oil  reservoir  of  brass  of  the  shape  of  an 
ordinary  plumb-bob,  the  stem  of  which  contains  the  wick. 
The  lamp  is  suspended  by  a  bail,  at  the  crown  of  which  is 
an  eye  for  the  cord  which  suspends  the  lamp.  When  sus- 
pended, the  cord,  the  flame  of  the  lamp,  and  the  point  of  the 
plumb-bob  are  in  the  same  vertical  line.  A  man  holds  the 
cord  against  the  roof  of  the  heading,  moving  it  right  or 
left  until  the  intersection  of  the  cross  wires  coincides  with 
the  flame  of  the  lamp.  A  point  is  then  marked  on  the  roof, 
and  a  hole  accurately  drilled  by  hand  to  a  depth  of  about 
three  or  four  inches.  A  plug  of  dry  pine  is  then  driven 
into  the  hole,  projecting  two  inches  below  the  roof.  The 
plug  is  carefully  centered  and  a  screw-eye  securely  fastened 
in  its  center,  from  which  a  plummet  lamp  may  be  suspended. 
A  piece  of  copper  wire  equal  in  length  to  the  full  height  of 
the  tunnel  is  attached  at  one  end  to  the  screw-eye  and  the 
other  end  fastened  to  the  wall  of  the  tunnel. 

When  the  full  section  of  the  tunnel  is  excavated,  a  plumb- 
bob  is  suspended  from  the  wire,  just  touching  the  floor  of 
the  tunnel.  A  hole  is  drilled  at  the  point,  plugged,  and 
centered,  as  on  a  surface  line.  For  bench  marks,  holes  are 
drilled  in  the  tunnel  wall  about  two  feet  above  the  floor, 
and  plugs  of  either  wood  or  iron  are  firmly  driven  and 
allowed  to  project  far  enough  from  the  wall  to  allow  the 
rod  to  be  held  upon  them  in  a  vertical  position.  In  testing 
the  grade  of  the  roof,  the  rod  is  held  in  an  inverted  position, 
the  foot  of  the  rod  being  placed  against  the  roof.  In  this 
case  the  elevation  of  the  roof  is  obtained  by  adding  the  rod- 
reading  to  the  height  of  instrument.     For  example,  suppose 


RAILROAD    CONSTRUCTION. 


961 


the  tunnel  section  is  24  feet  in  height,  the  floor  grade  at 
say  Station  160,  is  240.5  feet  and  the  height  of  the  instru- 
ment, which  is  standing  on  the  bench,  is  259.6  feet,  what 
should  the  rod  read  to  give  roof  grade  for  Station  IGO  ?  The 
floor  grade  at  Station  160  being  240.5  feet,  the  roof  grade 
will  be  240.5  feet  +  24  feet  (the  height  of  the  tunnel  section) 
which  is  264.5  feet.  As  the  height  of  instrument  is  259.6 
feet,  the  rod-reading  for  roof  grade  will  be  264.5  —  259.6  = 
4.9  feet.  A  common  bulls-eye  lantern  is  used  to  illuminate 
the  cross  hairs,  and  a  small  headlight  reflector  affords  the 
best  light  for  reading  the  level  rod  and  tape,  and  for  taking 
notes. 

1524.     Measuring  Excavation.  —  Various  methods 
are  adapted  for  checking  the  dimensions  of  the  tunnel  sec- 


Pig.  453. 

tion  and  measuring  up  the  work.  The  best  device  is  the 
following,  shown  in  Fig.  453.  A  semi-circular  protractor 
A  B  oi  a  diameter  from  8  to  10  feet,  and  made  of  light  pine, 


962  RAILROAD    CONSTRUCTION. 

is  set  up  at  right  angles  to  the  center  line  of  the  tunnel. 
The  diameter  A  B  oi  the  protractor  is  brought  into  a  hori- 
zontal position  by  means  of  the  spirit  level  C  and  placed  at 
any  desired  height  above  the  floor  of  the  tunnel.  A  sliding 
rod  D  E,  one  end  of  which  is  fastened  to  the  center  D  of 
the  protractor,  measures  the  distances  to  the  tunnel  walls  on 
radial  lines.  The  angles  which  these  lines  make  with  the 
horizontal  are  read  directly  from  the  protractor.  The  tun- 
nel section  and  the  actual  working  measurements  are  then 
platted  on  cross-section  paper,  from  which  the  amount  of 
excavation  is  readily  calculated. 

1525.  Plumbing  Shafts. — When  a  shaft  is  sunk  to 
increase  the  number  of  working  faces,  the  process  by  which 
the  center  line  is  transferred  from  the  surface  of  the  ground 
to  the  bottom  of  the  shaft  is  called  plumbing  the  shaft. 
Fig.  454  illustrates  the  process.  Two  pieces  of  plank  C  and 
D  are  spiked  to  the  shaft  timbers  where  the  center  line 
crosses,  the  edges  of  the  plank  projecting  over  the  shaft 
wall. 

Slots  E  and  E  are  cut  in  the  plank  on  the  center  line. 
An  iron  plate  with  a  carefully  drilled  hole  in  its  center  is 
placed  over  each  slot  with  the  center  hole  exactly  on  the 
center  line  of  the  tunnel.  Holes  are  drilled  in  the  corners 
of  the  plates  for  screws,  by  means  of  which  the  plates  are 
fastened  to  the  plank. 

Plumb-bobs  weighing  from  20  to  30  pounds  are  suspended 
by  fine  steel  wire  which  passes  through  the  eye-hole  in  the 
plate.  On  the  shaft  bottom  a  pail  of  oil  is  placed  directly 
under  each  plumb-bob,  which  is  entirely  immersed  in  the 
oil  to  check  the  vibrations.  When  the  plumb-bobs  come  to 
rest,  the  lines  which  suspend  them  are  exactly  in  the  center 
line  as  laid  down  on  the  surface  of  the  ground.  A  transit  is 
set  up  at  /  (the  tunnel  having  been  driven  some  distance 
from  the  foot  of  the  shaft)  and  moved  until  both  wires  are 
exactly  in  the  line  of  sight.  A  plug  is  then  set  on  the  line 
at  K,  after  which  the  instrument  is  moved  to  A'  and  a  plug 
set  at  /,  thus  establishing  the  line.  ' 


RAILROAD   CONSTRUCTION. 


9G3 


1526.  Ventilation.  —  In  clear  weather,  the  gases 
formed  by  the  combustion  of  the  powder  used  in  blasting 
pass  rapidly  from  the  tunnel  to  the  outer  air.  In  heavy 
weather,  and  especially  when  the  heading  is  at  a  consider- 
able distance  from  the  portal  or  shaft,  several  hours  are 
required  to  clear  the  tunnel  of  powder  smoke.     Under  such 


conditions  the  question  of  ventilation  becomes  an  important 
one.  In  order  that  a  man  may  do  effective  tunnel  work,  he 
should  have  a  supply  of  100  cubic  feet  of  pure  air  per  min- 
ute.    And  as  there  is  an  average  force  of  25  men  in   each 


964  RAILROAD   CONSTRUCTION. 

heading,  the  aggregate  supply  of  pure  air  per  heading  should 
therefore  be  2,500  cubic  feet  per  minute.  A  70-horsepower 
compressor  will  deliver  to  the  drills  about  500  cubic  feet  of 
free  air  per  minute,  and  there  will  still  be  required  for  ven- 
tilation the  difference  between  2,500  cubic  feet  and  500 
cubic  feet,  which  is  2,000  cubic  feet  per  minute. 

Exhaust  fans  with  air  pipes  leading  to  the  headings 
should  provide  the  balance  of  2,000  cubic  feet  per  minute. 
A  24-inch  air  pipe,  carrying  air  at  a  velocity  of  about  10  feet 
per  second,  will  provide  the  necessary  ventilation.  The  air 
pipe  should  reach  as  near  to  the  bench  as  may  be  without 
injury  from  blasts.  Contractors  are  invariably  negligent  in 
the  matter  of  ventilation,  causing  much  needless  suffering 
to  their  men  and  much  loss  to  themselves.  Men  can  not 
and  will  not  do  full  work  in  a  tunnel  reeking  with  powder 
smoke. 

Exhaust  fans  give  much  better  results  than  blowers,  as 
they  remove  the  foul  air  and  powder  smoke  direct  from  the 
heading,  instead  of  forcing  it  out  through  the  shaft  or  portal, 
as  in  the  case  with  blowers. 

1527.  Cost  of  Tunnel  Excavation. — The  cost  of 
tunnel  excavation  varies  widely,  depending  principally  upon 
the  character  of  the  material  excavated.  Firm  rock  of 
moderate  hardness  can  be  removed  at  from  $4.50  to  $0.50 
per  cubic  yard  for  the  entire  tunnel  section.  The  heading 
will  cost  about  40  per  cent,  more  than  the  balance  of  the 
section,  on  account  of  the  limited  space  for  working  drills 
and  the  greater  amount  of  powder  required  in  blasting. 
Where  unusual  obstacles  are  met,  the  cost  may  increase 
200  per  cent,  or  300  per  cent,  over  the  above  figures. 
Earthy  material  is  easily  broken,  but  the  expense  and  delay 
in  timbering  and  lining  brings  the  cost  to  about  the  same 
figures  as  for  solid  rock. 

1528.  A  Day's  Work  for   a  Machine  Drill. — An 

average  day's  work  for  a  machine  drill  in  heading  or  on 
bench  is  50  feet  of  2-inch  to  2^-inch  hole.  The  great  records 
made  on  the  surface  of  the  ground  are  not  possible  in  tun- 


RAILROAD   CONSTRUCTION.  OCTo 

nels  where  the  accumulated  muck  from  each  preceding  blast 
must  be  partially  removed  and  the  roof  trimmed  before  the 
columns  can  be  set  up.  Before  firing,  drills,  tripods,  bench 
hose,  and  scaffolding  must  be  removed  to  a  safe  distance, 
which  requires  considerable  time. 

1529.  Average  Progress  in  Driving. — Eight  sec- 
tions of  the  New  York  aqueduct  tunnel  gave  an  average 
monthly  progress  of  127  feet  for  full  section  of  about  IG  X 
16  feet.  The  average  weekly  progress  in  best  ten  headings, 
using  IngersoU  drills,  was  38.73  feet,  an  average  of  6. 45  feet 
per  day.  Average  monthly  progress  made  by  IngersoU 
drills  at  Vosburg  tunnel  on  the  Lehigh  Valley  Railroad  was 
202  feet,  the  tunnel  section  being  about  24  X  26  feet.  By 
hand  drills  the  average  monthly  progress  at  the  two  ends  of 
the  same  tunnel  was  61  and  73  feet,  respectively.  Material 
was  a  hard  gray  sandstone.  A  monthly  average  of  150  feet 
for  a  full  tunnel  section  is  first-class  work.  The  day  is 
divided  into  two  shifts  of  ten  hours  each.  There  is  an  hour's 
interval  for  changing  shifts,  and  a  dinner  hour  at  12  o'clock 
noon  and  12  o'clock  midnight.  • 

1530.  Lighting. — In  modern  tunnel  work  electric 
lights  are  almost  exclusively  used.  Oil  lamps  are  to  be 
condemned,  as  they  pollute  the  air.  Tallow  candles  may  be 
used  instead. 

1531.  Track  work  in  Tunnels. — In  laying  the  per- 
manent track,  only  first-class  material  is  admissible.  As  the 
roadbed  is  free  from  the  action  of  frost,  the  track,  after  two 
or  three  thorough  surfacings,  should  require  comparatively 
little  attention,  except  that  given  by  the  track  walker.  Rock 
ballast  is  invariably  used.  Ditches  should  be  large  enough 
to  secure  complete  drainage.  Oak  ties  are  to  be  preferred, 
of  uniform  dimensions,  and  spaced  18  inches  center  to  cen- 
ter of  tie.  Tunnel  ties  should  be  of  the  following  dimensions : 
Length,  8  feet;  breadth,  8  inches;  thickness,  7  inches. 
There  should  be  at  least  8  inches  of  rock  ballast  between 
bottom  of  tie  and  tunnel  floor,  giving  a  total   thickness  of 


966 


RAILROAD   CONSTRUCTION. 


ballast  of  15  inches.  When  the  tunnel  lining  has  an  invert, 
i.  e.,  when  the  section  of  the  floor  is  concave,  the  drain  is 
sometimes  built  under  the  track,  and  covered  with  flags  to 
prevent  clogging  with  ballast.  Side  ditches  are  to  be 
preferred,  as  they  are  always  accessible  and  easily  cleared. 


PROTECTION    WORK. 

1532.  Classification. — Under  this  head  will  be  con- 
sidered surface  ditches,  changing  channels  of  streams^  crib 
work,  paving,  etc. 

1533.  Surface  Ditches. — Surface  ditches  are  cut  at 
the  top  of  slopes,  but  at  sufficient  distance  from  them  to 
prevent  the  water  from  breaking  through  and  washing 
down  the  slope.  Where  the  natural  slope  of  the  ground  is 
towards  the  center  line  and  of  such  a  degree  that  a  large 
proportion  of  storm  water  runs  off,  the  surface  ditches 
should  be  cut  before  construction  commences.  When  this 
important  precaution  is  neglected,  it  often  occurs  that  a 
great  amount  of  storm  water  is  discharged  into  open  cuts, 
effectually  stopping  all  work  until  the  water  is  drained  off 


mi^///////////////'/////^^^^^ 

Pig.  455. 

and  the  ground  becomes  dry  enough  to  handle.  The  sight 
of  men  and  animals  floundering  in  flooded  cuttings  is  too 
common  in  railroad  work.  Many  contractors,  and  especially 
sub-contractors,  are  of  limited  experience,  financially  irre- 
sponsible, and  generally  follow  a  penny-wise  policy.  In  such 
cases,  the  engineer  in  charge  must  insist  on  such  precau- 


RAILROAD   CONSTRUCTION. 


967 


tions  being  taken  as  will  insure  a  vigorous  prosecution  of 
the  work.  Ditches  are  usually  paid  for  at  the  same  price 
per  cubic  yard  as  ordinary  excavation. 

Fig.  455  shows  a  section  of  a  surface  ditch  which  will  meet 
the  requirements  of  most  situations.  The  line  A  B  repre- 
sents the  natural  slope  of  the  ground ;  C,  the  surface  ditch ; 
B  D,  the  side  slope  of  the  cutting,  and  D  E,  the  half  width 
of  the  roadway.  The  center  line  of  the  road  is  denoted  by 
E  F. 

1534.  Changing  Channels  of  Streams. — It  fre- 
quently happens  when  the  line  of  road  is  parallel  to  the  gen- 
eral direction  of  a  stream  that  the  windings  of  the  stream 
repeatedly  cross  the  line  of  the  road. 

By  changing  the  channel  of  the  stream  at  favorable  points, 
a  great  saving  is  made  in  the  cost  of  construction.    A  situa- 


FIG.  456. 

tion  which  warrants  the  changing  of  a  channel  is  shown  in 
Fig.  456,  in  which  the  located  line  ABC  crosses  the  stream 
D  G  L  a.t  F  and  //,  requiring  an  expensive  bridge  at  each 
point.  By  cutting  a  channel  across  the  narrow  neck  E,  both 
bridges  are  avoided.  Such  instances  are  of  frequent 
occurence. 

1 535.  Crib  Work. — When  the  foot  of  an  embankment 
is  subject  to  the  erosion  of  a  current  of  water,  as  at  L  in  Fig. 
456,  a  crib  work  of  logs  and  stones  is  built  into  the  embank- 


968 


RAILROAD   CONSTRUCTION. 


ment  at  the  exposed  point.  Protection  cribs  are  ordinarily 
built  of  round  timber,  so  combined  as  to  form  compartments, 
which  are  filled  w'th  stone  to  give  them  stability  and  with- 


FlG.  457. 

stand  the  action  of  the  current.     A  general  plan  of  the  crib 
is  given  in  Fig.  457. 

Cribs  serve  the  purpose  both  of  retaining  walls  and  of  re- 
vetments. Their  chief  advantage  lies  in  their  adaption  to 
situations  where  the  cost  of  retaining  wall  foundations 
would  be  excessive.  They  can  be  readily  built  on  wet, 
marshy  soils  or  in  swift  running  water.  When  weighted 
with  stone,  the  structure  sinks,  and  additional  courses  are 
added  to  the  top  until  the  required  height  is  attained.  The 
usual  custom  is  to  excavate  a  pit  to  a  depth  of  from  12  to 
18  inches,  the  bottom  course  of  rangers,  i.  e.,  the  logs  run- 
ning lengthwise  in  the  crib,  being  laid  close  together.  Where 
there  is  danger  of  scour  from  the  current,  the  outside  com- 
partment is  sometimes  built  with  an  open  bottom.  As  the 
water  works  under  the  crib,  the  stone  drops  from  the  com- 
partment above,  forming  a  rip  rap  which  prevents  further 
action  of  the  current.  The  lower  courses  of  the  crib,  being 
kept  constantly  moist,  are  free  from  decay.  The  earth  and 
sand  from  the  sustained  embankment  are  gradually  washed 
into  the  cavities  in  the  ballast  until  the  whole  forms  one 
compact  mass  of  great  strength  and  solidity.  In  Fig.  457 
A  B  is  the  front  elevation,  the  line  A  B  being  parallel  to  the 


RAILROAD   CONSTRUCTION. 


969 


direction  of  the  current,  C  D  shows  a  section  of  the  crib, 
and  E  the  foot  of  the  embankment  which  slopes  away  at  the 
natural  slope  of  earth,  viz.,  1^  to  1.  A  plan  of  the  crib 
is  shown  at  F  and  the  foot  of  the  embankment  by  the  broken 
line  G  H.  A  detail  of  a  joint  is  shown  at  K.  The  log  Z, 
corresponding  to  r  j  in  the  elevation,  is  called  a  ranger ; 
and  the  log  il/,  corresponding  to  C  Dm.  the  section,  is  called 
a  cross-tie  or  tie.  At  each  joint  a  drift  bolt,  usually  a 
piece  of  f-inch  round  iron  sharpened  at  one  end,  is  driven  to 
fasten  the  logs  together.  The  bolt  should  be  of  sufficient 
length  to  pass  through  three  logs.  A  hole  of  slightly 
less  diameter  than  the  bolt  is  bored  to  receive  the  bolt.  A 
compartment  filled  with  stone  is  shown  at  O. 

1536.  Paving. — Paving  as  applied  to  protection  work 
consists  of  a  stone  covering  laid  on  the  surface  of  embank- 
ments where  they  are  exposed  to  the  action  of  water.  The 
paving  is  usually  12  inches  in  depth  and  composed  of  good- 


FiG.  468. 

sized  stone  of  fairly  regular  shape  and  even  beds,  the  beds 
being  laid  perpendicular  to  the  slope  of  the  embankment, 
and  when  finished  the  whole  to  present  a  fairly  uniform  sur- 
face. The  slope  of  the  embankment  should  be  smoothed  and 
well  rammed  before  the  paving  is  laid. 

A  foundation  course  of  heavy  stones  A,  Fig.  458,  is  laid 
at  the  foot  of  the  embankment  in  a  pit  from  12  to  18  inches 
in  depth,  depending  upon  the  nature  of  the  soil.  When  the 
stream   has  a    rocky    bed    the    foundation    course    is  laid 


970  RAILROAD   CONSTRUCTION. 

upon  the  surface.  The  profile  of  the  surface  of  the 
ground  is  shown  by  the  irregular  line  B  C\  the  earth 
embankment  by  D\  the  bed  of  the  stream  by  E  F\  the  sur- 
face of  low  water  by  G  //,  and  of  high  water  by  L  M, 
The  elevation  of  the  protected  surface  is  shown  at  K,  with 
the  joints  of  the  stones  well  broken.  The  grade  of  the 
roadway  is  indicated  by  the  line  N  O. 


ROUTINE    WORK. 

1537.  Routine  Work  of  the   Engineer  Corps. — 

The  initial  work  of  the  construction  corps,  viz.,  the  checking 
and  betterment  of  the  alinement,  the  referencing  of  transit 
points  and  cross-sectioning,  together  with  the  location  and 
conduct  of  tunnel  work,  have  already  been  described.  The 
routine  work  which  occupies  the  engineers'  time  from  the 
commencement  of  the  construction  to  its  completion  will  be 
considered  under  one  head. 

1538.  To  Lay  Out  a  Culvert  at  Right  Angles  to 
the  Center  Line,  W^hich  is  a  Tangent:  The  rule  for 
laying  out  box  culverts  was  given  m  Art.  1462.  The 
stakes  for  pit  excavations  and  for  neat  lines  of  masonry  are 
arranged  as  shown  in  Fig.  459. 

The  broken  lines  show  the  outlines  of  the  foundation  pit, 
which  extends  from  six  to  twelve  inches  outside  the  neat 
lines  of  the  masonry,  depending  upon  the  depth  of  the 
foundation.  Ordinarily  six  inches  is  sufficient.  The  pit 
should  be  large  enough  to  permit  a  thorough  inspection  of 
the  masonry.  The  face  lines  of  the  masonry  are  located  with 
the  transit.  The  center  line  X  Fof  the  culvert  being  at 
right  angles  to  the  center  line  P  Q  oi  the  road,  a  plug  is  set 
at  K,  Fig.  459,  at  the  intersection  of  the  center  line  of  the 
road  and  the  center  line  of  the  culvert.  The  instrument  is 
then  set  up  at  K  and  a  right  angle  turned  in  the  line  X  V 
for  locating  face  lines.  The  height  of  the  embankment  at 
this  point  is  nine  feet ;  the  culvert  opening  two  feet  wide  and 
two  feet  high ;  the  covering  flags  are  one  foot  thick,  and  the 
parapet  one  foot  high.     Then,  according  to  the  rule  for  find- 


RAILROAD   CONSTRUCTION. 


971 


ing  the  dimensions  of  a  box  culvert,  given  in  Art.  1462, 
we  have  9  feet  —  4  feet  =  5  feet;  1^  X  5  feet  =  7. 5 feet;  7.5 
feet  +  1.5  feet  =  9.0  feet ;  9  feet  +  8  feet,  the  half-width  of  the 
roadway  =17  feet,  the  distance  from  center  line  of  road  to 
the  end  of  the  culvert.  We  then  measure  on  the  line  X  V  the 
distance  K  L  =  17  feet,  setting  a  plug  at  L.  On  the  same 
line  six  or  eight  feet  from  L  set  a  temporary  point  M.  Then, 
set  large  stakes  at  A  and  C,  twelve  inches  from  M,  in  lines 
at  right  angles  to  L  J/,  estimating  the  angles  by  the  eye. 
Measure  accurately  the  distances  MA  and  MC,  each  twelve 
inches,  and  drive  a  lath  nail  in  both  stakes,  checking  the 
distance  ri  6^=24  inches.  Then,  reverse  the  instrument, 
setting  a  plug  at  ^V,  17  feet  from  K,  and  a  point  at  O  for 
locating  the  stakes  at  B  and  D,  checking  the  measurements 


<  ip" 


A 


tI 


rrHl 


-W'i- 


<^K- 


l=U 


*B 


P 
Fig.  459. 


iLj 


G* 


-Oo-T 


as  at  A  and  C.  Next,  set  the  instrument  at  iVand  turn  the 
angle  A'A^//'=  90°.  Applying  the  rule  given  in  Art.  1462, 
for  finding  the  length  of  wing  walls,  we  have  2  feet,  the 
height  of  abutments  +  1  foot,  thickness  of  flags  =  3  feet; 
1|  X  3  feet  =  4.5  feet;  4.5  feet  +  2  feet  =0.5  feet,  the  dis- 
tance from  the  face  of  the  opening  to  the  end  of  wing  wall. 
On  the  line  N  //set  a  stake  at  H,  ten  or  twelve  feet  from  N, 
and  drive  a  lath  nail  in  the  stake  on  line.  Reverse  the 
instrument,  and  at  the  same  distance  from  N  set  a  stake  at 
G,  with  a  tack  on  line.  Next  move  the  instrument  to  L,  and 
turning  a  right  angle  to  X  V,  set  stakes  at  E  and  F.  With 
these  stakes  for  a  guide,   the  engineer  can  locate  the  pit 


972  RAILROAD   CONSTRUCTION. 


■rt 


t 


fr- 


\ 


corners  with  the  tape  alone.  A  stake  is  driven  at  each 
corner  of  the  pit,  and  after  the  excavation  is  made  and  the 
paving  is  laid,  cord  is  stretched  from 
the  tacks  in  the  stakes  from  A  to  B^  C 
to  D,  E  to  F,  and  G  to  H ,  marking  the 
face  lines.  All  other  needed  lines  the 
mason  can  lay  out  for  himself. 

1539.     When  the  Center  Line 
of    the     Road     is    a    Curve. — On 

curves,  as  on  tangents,  wherever  pos- 
sible, th«  center  line  of  the  culvert  is 
placed  at  right  angles  to  the  center 
line  C  L  on  the  road,  i.  e.,  at  right 
FIG.  460.  angles   to   the   tangent   D  E  oi   the 

curve  at  the  center  D  of  the  culvert  (see  Fig.  460).  The  wing 
walls  F  and  G  are  parallel  to  this  tangent.  The  dimensions 
of  a  culvert  on  a  curve  are  the  same  as  those  on  a  straight 
line,  with  the  same  height  of  embankment. 

1540.  When  the  Center  Line  of  the  Culvert 
Makes  an  Oblique  Angle  with  the  Center  Line  of 
the  Road,  i.  e.,  W^hen  the  Culvert  is  Askew. — First 
find  what  the  length  of  the  culvert  would  be  if  it  were  at 
right  angles  to  the  center  line  of  the  road.  This  will  give 
the  base  of  a  right-angled  triangle,  one  of  whose  angles  is  the 
angle  of  skew.  The  other  is  easily  found  by  subtracting 
the  angle  of  skew  from  90°.  The  hypotenuse  will  be  the 
required  side  distance.  The  wing  walls  must,  in  all  cases, 
be  parallel  to  the  center  line  of  the  road. 

Example. — A  railroad  embankment  is  12  feet  in  height.  A  box 
culvert  with  opening  3  feet  wide  and  3  feet  high  must  be  built  askew 
at  an  angle  of  70°  with  the  center  line.  What  is  the  distance  from  the 
center  line  of  the  road  to  the  center  of  the  opening  at  the  face  of  the 
culvert  ? 

Solution. — Let  A  B,  Fig.  461,  be  the  center  line  of  the  road,  and 
CD  the  center  line  of  the  culvert,  .-/  K C  =  70^  being  the  angle  of  skew. 
At  A' draw  E  Fat  right  angles  to  A  B.  From  the  given  dimensions  of 
culvert  and  height  of  embankment,  we  have  for  a  right-angled  culvert, 
side    distances   as    follows:    12  —  5  =  7,  H  X  7  =  10.5,    10.5 -h  1.5  =  12, 


RAILROAD   CONSTRUCTION. 


973 


12  -h  8  =  20  feet,  the  side  distance.  Lay  off  on  K E  the  distance  KG  = 
20  feet.  Draw  G  H  perpendicular  to  KG,  forming  the  right-angled 
triangle  K  G  H,  ot  which  the  angle  G  K  H  =W  and  the  side  K  G  = 


Fig.  461. 


20  feet.     The  side  length,  which  is  the  hypotenuse  K  H,  is  found  by 


the  formula  cos  20° 
20 


gA'=20feet 
hypotenuse  K  H 


,  or  hypotenuse  K H . 


20 


cos  20° 


Tioki;?;  -  21.28  feet  =  the  side  distance.     Ans. 
.yoyby 

The  wing  walls  for  a  right-angled  culvert  of  the  given 
dimensions  would  have  a  length  of  1^x4=6;  6  +  2  =  8 
feet.  Their  length  L  M  for  the  given  culvert  is  found  by 
the  following  proportion : 

20  ft.  :  21.28  ft.  ::8  ft.  :  L  M, 

21.28  X  8 


whence  the  length   of  skewed  wing  wall  L  M  =^ 


20 


8.51  feet. 

Side  and  wing  walls  are  2^  feet  thick  and  covering  stones 
1  foot  thick.  The  dimensions  of  the  foundation  pit  are  pro- 
portionately the  same  as  in  Fig.  459.  The  stakes  for  the 
neat  lines  of  the  masonry  are  located  as  in  that  figure. 

Skewed  culverts  are  of  greater  length  and  contain  more 
material  than  those  at  right  angles  to  center  line  of  road, 
and,  when  arched,  they  are  much  more  costly  to  build. 
Considerable  expense  may,  therefore,  be  properly  incurred 
in  altering  a  channel  so  as  to  obtain  a  right-angled  crossing. 


974  RAILROAD   CONSTRUCTION. 

1541.  Borrow  Pits. — Borrow  pits  are  excavations 
made  for  the  purpose  of  obtaining  additional  material  for 
embankments  when  the  regular  excavation  does  not  furnish 
an  adequate  supply.  The  simplest  form  of  borrow  pit  is  a 
trench  dug  parallel  to  the  center  line,  a  space  of  suitable 
width  being  left  between  the  slope  stakes  and  the  edge  of 
the  pit.  This  space,  or  berme,  as  it  is  called,  should  be 
six  feet  in  width.  Formerly,  much  of  the  material  taken 
from  such  borrow  pits  was  handled  with  wheelbarrows.  In 
modern  practice,  where  the  material  admits  of  it,  the 
wheeled  scraper  is  invariably  used.  The  amount  of  ma- 
terial needed  for  the  embankment  in  excess  of  that  fur- 
nished by  the  adjacent  cuts  is  readily  calculated.  This 
excess  is  first  excavated  from  side  borrow  pits  and  deposited 
in  place,  after  which  the  material  from  the  adjacent  cuttings 
is  added. 

Another  means  of  borrowing  material,  and  one  which  is 
always  adopted  where  the  haul  is  not  too  great,  is  by  widen- 
ing the  cuts.  In  proportion  as  the  cut  is  widened,  the 
danger  of  the  ditches  being  filled  up  by  caving  embankments 
or  snow  is  removed. 

Where  embankment  is  made  from  material  cast  from  the 
sides  of  the  road,  the  berme  is  rarely  more  than  four  feet  in 
width.  When  the  building  of  a  road  is  only  possible 
through  the  exercise  of  the  greatest  economy,  a  berme  of 
four  feet  is  admissible,  even  though  it  may  involve  increased 
expense  at  some  future  time.  Side  work  of  this  kind  has 
been  let  on  some  of  the  cheap  Dakota  lines  at  a  price  as  low 
as  12  cents  per  cubic  yard,  with  an  average  height  of  em- 
bankment of  2  feet.  These  lines  were  built  through  an 
unsettled  country,  and  carried  the  settlers  who  were  to  fur- 
nish the  future  business  for  the  road.  As  the  country  set- 
tled up  and  traffic  increased,  these  roads  were  practically 
rebuilt.  The  original  grade  lines,  whenever  practicable, 
followed  the  undulations  of  the  prairie.  In  rebuilding, 
these  grades  were  greatly  improved  by  filling  up  the  sags. 
On  many  sections  the  amount  of  material  added  was  double 
that  put  in  the  original  work. 


RAILROAD   CONSTRUCTION. 


975 


fi^. 


loa 


1542.  Calculating  the  Contents  of  Borrow 
Pits. — Where  the  entire  embankment  is  made  from  side 
borrow  pits,  the  contents  of  the  embankment  with  an  allow- 
ance for  shrinkage  is  taken  as  the  contents  of  the  pits. 
This  process  of  measurement  saves  work  and  is  more 
accurate  than  measuring  the  dimensions  of  the  several  pits, 
especially  when  they  are  made  with  wheeled  scrapers  which 
leave  the  pits  in  irregular  shape. 

When  the  cuts  are  widened  for  borrowed  material,  the 
surface  cross-sections  are  extended  far  enough  to  include  the 
additional  excavation.  After 
the  work  is  completed,  the 
cross-sections  are  again 
taken.  Both  cross-sections 
are  platted  on  the  same  sheet, 
which,  at  once,  shows  the 
amount  of  the  excavation. 

Frequently  the  embank- 
ment is  many  times  greater 
in  volume  than  the  tributary 
cuttings,  involving  an  ex- 
tended borrow  pit.  In  such 
cases  the  cross-sections  some- 
times extend  several  hun- 
dred feet  from  the  center 
line.  Fig.  462  shows  a  bor- 
row pit  of  this  character  with 
the  usual  form  of  cross- 
section. 

In  this  figure  the  proposed 
borrow  pit  is  situated  on  the 
left  of  the  center  line,  and 
the  cross-sections  include  an 
area  extending  in  length 
from  station  100  to  station 
105,  and  in  width  250  feet  from  the  center  line.  A  bench 
mark  is  established  at  a  convenient  distance  from  the  bor- 
row pit,   to   be   used  in  taking  cross-sections  for  monthly 


c:  S*  ®  J5 
»^  e«  ©  *^ 

«♦  ©»  *j  "^ 


•s   *^   •«< 
Fig.  462. 


104 


109 


102 


101 


lOOtM 
lOO 


976  RAILROAD   CONSTRUCTION. 

estimates  and  final  cross-sections.  The  surface  levels  are 
taken  as  follows:  Stakes  are  driven  on  the  center  line 
25  feet  apart,  commencing  at  station  100,  and  an  equal 
number  at  corresponding  points  on  a  line  350  feet  from  and 
parallel  to  the  center  line.  A  rope  250  feet  in  length,  with 
tags  tied  at  intervals  of  25  feet,  is  stretched  from  station 
100  to  the  stake  at  A,  250  feet  distant.  '  A  rod  reading  is 
then  taken  at  each  25-foot  tag  and  recorded.  The  line  is 
then  moved  forward  25  feet,  one  end  being  held  at  station 
100 -{-25,  and  the  other  at  B,  and  the  levels  on  this  line 
taken.  In  the  same  way  the  entire  surface  is  covered. 
This  arrangement  divides  the  surface  into  squares  of  25  feet 
on  a  side.  For  monthly  and  final  estimates  the  cross- 
sections  are  taken  at  the  same  points,  which  insures  accuracy 
and  greatly  simplifies  calculation. 

The  surface  sections  are  platted  on  cross-section  paper, 
and  placed  far  enough  apart  on  the  sheet  to  avoid  over- 
lapping when  the  monthly  and  final  sections  are  platted. 
The  cross-sections  for  each  monthly  estimate  are  platted  in 
a  different  color,  excepting  the  surface  and  final  sections, 
which  are  in  black.  Cross-section  books,  the  leaves  of 
which  are  ruled  like  standard  cross-section  paper,  are  very 
convenient  for  platting  sections  of  borrow  pits  and  special 
excavations.  They  may  be  used  in  the  field,  like  ordinary 
note-books,  the  notes  being  recorded  in  pencil,  and  inked 
in  at  the  office  when  leisure  time  permits.  For  platting 
work  of  this  kind,  cross-section  books  are  far  prefer- 
able to  loose  sheets,  which  are  sure  to  become  soiled  from 
repeated  use,  and,  in  spite  of  the  greatest  care,  some  are 
lost. 

1543.  Checking  the  Center  Line. — During  con- 
struction, and  especially  on  embankments,  the  center  line 
should  be  frequently  checked,  i.  e.,  run  in  on  the  incom- 
pleted embankment.  All  materials  will  not  at  once  take 
the  natural  slope  of  1^  horizontal  to  1  vertical.  Frequently 
the  embankment  becomes  one-sided,  and  a  line  of  centers 
reveals  at  once  any  irregularity.     Contractors  of  ten  sustain 


RAILROAD   CONSTRUCTION.  977 

a  loss  on  account  of  material  being  wasted.  It  is  the  duty 
of  the  engineer  to  restore  centers  whenever  they  are  needed, 
whether  asked  for  or  not. 

1544.  Grade  Stakes. — When  the  roadway,  either  in 
cutting  or  on  embankment,  is  brought  approximately  to 
grade,  a  grade  stake  is  set  at  intervals  of  100  feet.  On 
embankments  the  stake  is  driven  on  the  center  line,  with 
its  top  at  grade.  In  cuttings  the  stake  is  driven  at  the  side 
of  the  roadway,  and  a  peg  is  driven  near  the  foot  of  the 
stake.  The  elevation  of  the  top  of  the  peg  is  taken,  and 
the  amount  of  cutting  which  must  be  made  below  the  top 
of  the  peg  to  reach  the  grade  line  is  written  upon  the 
stake. 

1545.  Care  of  Stakes. — The  destruction  of  stakes 
by  contractors'  workmen,  and  the  disregard  of  them  by 
contractors  themselves  and  their  foremen,  is  about  universal. 
There  is  no  regularly  prescribed  penalty  for  such  criminal 
carelessness.  The  cost  of  restoring  stakes  should  be  charged 
to  the  contractor  at  double  price.  A  literal  enforcement  of 
specifications  in  minor  details,  where  they  might  be  relaxed 
to  the  advantage  of  the  contractor  and  with  no  detriment 
to  the  railroad  company,  has  caused  many  a  contractor  to 
regret  his  carelessness  in  this  matter.  A  trick  of  dishonest 
contractors  is  to  move  slope  stakes  nearer  to  the  center  line, 
and  so  reduce  the  quantity  of  excavation  or  of  embank- 
ment. An  alert  engineer  will  soon  get  the  true  measure 
of  the  contractors  under  him,  and  detect  deceit  of  this 
kind. 

1546.  Provision  for  Settling. — Embankments  are 
raised  from  5  to  10  per  cent,  above  the  established  grade  to 
provide  for  the  shrinkage  which  invariably  takes  place  in  all 
earth  embankments.  The  amount  of  this  percentage  is 
fixed  by  the  engineer  in  charge,  and  depends  upon  the 
nature  of  the  material  composing  the  embankment.  Com- 
pact clay  or  gravel  will  noL  settle  or  shrink  more  than  half 
as  much  as  soft  alluvial  soils. 


978  RAILROAD   CONSTRUCTION. 

1547.  Overhaul. — Many  contracts  for  railroad  work 
specify  the  maximum  distance  to  which  material  shall  be 
transported  at  the  given  price  per  yard.  When  the  distance 
exceeds  that  specified  in  the  contract,  the  excess  is  termed 
overhaul,  and  a  clause  in  the  contract  stipulates  what  addi- 
tional compensation  shall  be  made  for  each  hundred  feet  of 
overhaul.  Free  haul  \s  commonly  limited  to  1,000  feet,  and 
for  each  hundred  feet  of  overhaul  an  addition  of  1  cent 
per  cubic  yard  is  made  to  the  contract  price  per  yard.  In 
recent  years  the  overhaul  clause  is  omitted  from  most 
contracts,  as  it  is  almost  sure  to  involve  litigation. 


BRIDGE  WORK. 

1548.  The  Location  of  Bridges. — There  are  two 
important  factors  in  the  location  of  a  bridge,  viz.,  first,  the 
determination  of  the  angle  which  the  center  line  of  the 
road  shall  make  with  the  general  direction  of  the  channel, 
and,  second,  the  measurement  of  the  span. 

In  all  cases  it  is  desirable  that  there  should  be  a  right- 
angled  crossing,  and  for  bridges  of  large  span  the  aline- 
ment  is  often  modified  to  obtain  that  result.  The  amount 
of  such  modification,  if  any,  will  depend  upon  the  impor- 
tance and  character  of  the  traffic.  If  the  line  is  for  through 
business  where  numerous  passenger  trains  are  to  be  run  at 
high  speed,  the  angle  of  the  crossing  will  be  subservient  to 
the  alinement;  that  is,  a  skewed  bridge  will  be  adopted 
rather  than  to  introduce  curvature  and  mar  the  directness 
of  the  line. 

Skewed  bridges  are  always  more  expensive  and  generally 
less  satisfactory  than  those  crossing  streams  at  right  angles. 

The  character  of  the  crossing  being  determined  upon, 
the  next  thing  in  order  is  the  measurement  of  the  span. 
This  may  be  effected  in  two  ways,  and,  when  practicable, 
both  methods  should  be  used,  the  one  serving  as  a  check 
upon  the  other.  The  first  method  is  by  direct  measure- 
ment; the  second  by  triangulation.  Before  either  method 
is  applied,  the  center  line  must  be  accurately  checked  and 


RAILROAD   CONSTRUCTION.  979 

established  by  fixed  monuments  set  on  both  sides   of   the 
stream. 

1 549.  Direct  Measurement  of  Span. — The  direct 
measurement  of  the  span  is  made  as  follows:  A  light  strong 
steel  wire  is  stretched  from  monument  to  monument, 
spanning  the  stream.  One  end  of  the  wire  is  fixed  so  that 
the  wire  is  either  in  actual  contact  with  the  point  in  the 
monument  or  directly  over  it.  To  the  other  end  a  spring 
balance  is  attached,  which  indicates  by  a  dial  the  amount  of 
tension  placed  upon  the  wire. 

The  wire  is  then  stretched  until  the  sag  is  practically 
removed,  and  the  amount  of  tension  noted.  If  the  wire  is 
not  in  direct  contact  with  the  monument  centers,  the 
measurement  is  found  by  plumbing  from  the  wire  to  the 
monuments.  The  points  of  measurement  are  then  marked 
on  the  wire  and  the  measurement  repeated.  The  measure- 
ment should  be  made  at  least  three  times,  the  wire  being 
subjected  to  the  same  tension.  As  one  end  of  the  wire  is 
fixed,  any  variations  in  measurement  will  show  at  the  free 
end.  If  the  measurements  show  any  considerable  variation, 
the  process  must  be  repeated  until  tJiree  measurements 
practically  agree.  Two  supports  are  then  erected  upon  a 
level  surface,  at  a  distance  from  each  other  equal  to  the  span 
of  the  stream,  and  of  such  height  that  the  wire  w///  clear  the 
groujid  when  stretched  between  the  supports  at  the  same 
tension  as  used  in  the  original  measurement.  The  wire  is 
then  stretched  with  the  proper  tension,  and  the  points  of 
measurement  transferred  to  the  ground  by  plumbing.  The 
measurement  on  the  ground  is  made  with  a  standard  steel 
tape,  and  repeated  three  times.  The  average  of  the  three 
measurements,  providing  their  discrepancy  is  slight,  may  be 
accepted  as  the  correct  measurement  of  the  span. 

1550.  Measurement  of  the  Span  by  Triangula- 
tion. — If  practicable,  the  same  monuments  used  in  direct 
measurement  are  used  in  triangulating.  The  first  step  is 
the  establishing  of  a  base  line,  which  should  be  of  approxi- 
mately the  sajue  length  as  the  span,  and  laid  out  on  as  smooth 


980  RAILROAD   CONSTRUCTION. 

ground  as  the  situation  will  permit.  The  measurement  of 
the  base  line  is  made  with  the  greatest  care  and  repeatedly 
checked.  When  the  ground  is  practically  level  the  following 
method  is  recommended  (see  Fig.  463):  Strong  stakes  are 
driven  at  A,  B,  C,  etc.,  approximately  100  feet  apart,  their 
tops  being  on  the  same  level  and  pointed,  with  a  small  tack 
in  each  stake.  The  spaces  between  the  stakes  are  then 
measured  with  a  steel  tape  at  a  tension  of  about  15  pounds. 
The  measurements  are  made  three  times,  and  the  average 
of  them  taken  as  correct.  Greater  accuracy  in  measure- 
ment is  secured  by  having  different  persons  read  the  tape 
for  each  measurement,  each  recording  his  own  reading,  and 
after  the  third  reading  place  the  three  readings  in  a  column 


and  take  the  average  for  the  correct  measurement.  The 
sum  of  the  averaged  measurements  will  be  the  length  of  the 
base  line  A  G.  Suppose  for  this  case  that  they  are  as 
follows: 

99.892 

99.997 

99.8963 

99.957 

99.9466 

99.880 


699.5689  feet, 

which  gives  f.or  the  total  length  of  the  ^<2;jf' //«^  599. 5689  feet. 
Let  Fig.  464  be  the  plan  of  the  bridge  crossing.  A  and 
G  are  monuments  in  the  center  line  on  each  side  of  the 
river,  and  B  G  the  base  line^  whose  length  we  have  deter- 
termined  by  direct  measurement  to  be  599.5689  feet.  The 
angles  at  A,  Z>',  and  G  are  measured  three  times,  and  the 
average  of  the  readings  taken  as  the  correct  reading.  It  is 
desirable  to  use  a  transit  which  will  read  to  10  seconds,     On 


RAILROAD   CONSTRUCTION.  981 

bridges  of  great  length  the  angle  readings  are  taken  in  three 
sets  of  five  readings  each,  and  the  average  of  all  accepted 
as  the  correct  reading.  This  mode  of  angle  measurement 
was  adopted  in  measuring  the  span  of  the  Washington 
bridge  over  the  Harlem  river,  at  New  York.  Suppose  that 
the  average  of  three  readings  makes  the  angle  at  A^ 
57°  29'  35";  at  B,  59°  01'  03.3"  and  at  G,  63°  39'  20".  Their 
sum  is  equal  to  179°  59'  58.3*,  which  proves  the  angle  meas- 


FIG.  464. 

urement  to  be  practically  correct.  The  length  of  the  side 
A  G,  i.  e.,  the  span,  is  determined  by  the  principles  of 
trigonometry  (see  Art.  1243),  as  follows: 

Sin  57°  29'  35'  :  sin  59°  01'  03.3' ::  599.5G9  :  side  A  G. 

sin  59°  01' 03.3' =  .85733 
599.569  X  .85733  =  514.028491 

sin  57°  29'  35' =.84333 
514.028491 


.84333 


=  609.522  ft.  =side^  G. 


If  the  temperature  of  the  air  in  this  case  were  60°  Fahren- 
heit, it  may  be  considered  normal,  so  that  there  need  be  no 
allowance  made  for  the  expansion  or  contraction  of  the 
tape.     The  base  line  B  G'\s  practically  parallel  to  the  direction 


982  RAILROAD   CONSTRUCTION. 

of  the  channel  current  as  indicated  by  the  arrow,  and 
the  angle  at  G  of  63°  29'  20'  will  be  the  angle  of  skew  to 

which  the  bridge  will  be  built. 

i 

1551.  The  Location  of  Piers  and  Abutments. — 

The  number  of  piers  to  be  built  will  depend  upon  whether 
the  stream  is  navigable  or  not,  and  upon  the  cost  of  founda- 
tions. If  the  stream  is  navigable  there  must  be  one  channel 
span  of  such  width  as  the  Government  authorities  shall 
determine. 

When  no  provision  is  required  for  navigation,  the  cost  of 
foundations  alone  will  determine  the  number  of  piers.  In 
general,  the  cost  of  bridges  will  increase  about  as  the  square 
of  the  span ;  that  is,  if  07ic  bridge  is  of  twice  the  span  of  an- 
other, the  first  will  cost  about  four  times  as  much  as  the 
second.  If  the  stream  is  shallow  and  its  bed  of  rock  or  com- 
pact gravel  or  clay,  suitable  for  foundations,  it  will  be 
cheaper  to  increase  the  number  of  piers,  and  shorten  the 
spans  proportionately. 

1552.  Foundations. — This  subject  is  too  broad  for 
any  but  general  treatment.  A  bridge  foundation  must  meet 
two  conditions,  viz.,  stability  and  security;  that  is,  it  must 
be  able  to  safely  support  the  maximum  load  imposed  upon 
it,  and  must  be  protected  against  those  natural  forces  which 
either  periodically  or  continually  attack  it.  The  principal 
enemies  of  bridge  foundations  are  the  erosive  action  of  the 
current  and  floating  ice,  both  of  which  are  most  active  at 
high  stages  of  water.  Bridge  piers,  with  few  exceptions, 
are  of  stone.  Pier  foundations  may  be  divided  into  three 
classes,  viz.,  rock  ox  concrete  foundations, ///i"  foundations, 
and  caisson  foundations. 

1553.  Rock  and  Concrete  Foundations. — When 
the  bed  of  the  stream  is  rock  or  compact  gravel,  sand,  or 
clay,  the  pier  site  is  prepared  as  follows:  When  of  rock, 
trenches  equal  in  width  to  the  thickness  of  the  outside  walls 
of  the  pier  are  excavated  to  a  depth  of  12  inches.  The 
bottom  of  the  trench  is  brought  to  the  same  general  level, 


RAILROAD   CONSTRUCTION.  983 

and  a  layer  of  concrete  added  to  furnish  an  even  bed  for  the 
masonry.  As  foundations  are  generally  built  at  low  stage 
of  water,  the  action  of  the  current  is  but  slight. 

When  compact  sand  or  hard  clay  forms  the  bed  of  the 
stream,  a  dam  is  built  enclosing  the  foundation  site.  If  the 
water  is  stagnant  and  of  a  depth  not  exceeding  4  feet,  a 
trench  is  dug  from  12  to  24  inches  in  depth,  enclosing  the 
foundation,  and  the  trench  is  then  filled  with  clay  and  gravel, 
well  mixed  and  thoroughly  rammed,  forming  a  wall  which 
is  carried  above  the  surface  of  the  water.  The  enclosed 
water  is  then  pumped  out  and  the  foundation  area  excavated 
to  a  depth  of  from  12  to  24  inches,  depending  upon  the 
erosive  force  of  the  current  and  the  weight  of  the  proposed 
pier.  The  pit  is  then  filled  with  well-rammed  hydraulic 
concrete,  and  the  masonry  laid  precisely  as  on  shore.  The 
two  lower  courses  of  masonry  are  stepped  outwards,  that  is, 
they  project  beyond  the  main  body  of  the  pier,  increasing 
the  bearing  surface  of  the  foundation.  These  footings  or 
offsets  are  made  from  4  to  0  inches  wide.  The  foundation 
courses  should  be  of  larger  stones  than  those  composing 
the  main  body  of  the  pier.  The  faces  of  the  pier  are  usually 
battered  from  |-  to  1  inch  horizontal  to  1  foot  vertical. 
Where  the  piers  must  resist  heavy  masses  of  floating  ice, 
the  up  stream  ends  are  brought  to  an  edge,  forming  ice 
breakers. 

1554.  Cofferdams. — For  depths  of  stagnant  water 
greater  than  four  feet  and  for  less  depths  having  a  current, 
the  clay  dam  is  replaced  by  a  cofferdam.  This  construc- 
tion consists  of  two  rows  of  piles  which  are  driven  enclosing 
the  foundation  site.  The  distance  apart  of  these  rows  of 
piles,  as  well  as  the  spacing  of  the  piles  in  the  rows,  will  de- 
pend upon  the  depth  of  the  water  surrounding  the  founda- 
tion site,  and  the  nature  of  the  material  into  which  the  piles 
are  to  be  driven.  The  piles  will  also  be  required  to  support 
a  platform,  upon  which  are  placed  the  derricks,  hoisting 
machinery,  and  building  material  used  during  construc- 
tion. 


^84 


RAILROAD   CONSTRUCTION. 


The  usual  form  of  construction  of  a  cofferdam  is  shown  in 
Fig.  465.  Two  rows  of  piles  /*,  P  are  firmly  driven,  enclo- 
sing the  foundation  area. 
Longitudinal  pieces  of 
squared  timber  Wy  Uncalled 
string  pieces  or  wales 
are  bolted  to  the  piles  a 
little  above  the  water  level. 
Directly  opposite  the  string 
pieces  on  the  inside  of  the 
piles,  guide  pieces  g^  g 
are  bolted,  the  same  bolt 
passing  through  both  string 
piece  and  guide.  The 
guide  pieces  serve  to  keep 
the  sheet  piles  5,  5  in  line 
while  being  driven.  Cross 
timbers  B^  B  called  bind- 
ers are  notched  down  on 
the  string  pieces  to  which 
they  are  bolted.  The  de- 
positing and  ramming  of 
the  puddle  tend  to  cause 
the  rows  of  piles  to  spread. 
The  bindei:s  prevent  this  and  give  strength  and  stability  to 
the  structure.  The  plank  flooring  e  supports  the  derricks, 
hoisting  machinery,  building  material,  etc.  The  consistency 
of  the  cofferdam  filling  must  be  such  as  to  exclude  the 
water,  and  the  weight  and  strength  of  the  entire  structure 
must  be  sufficient  to  resist  the  pressure  of  the  excluded 
water.  Taking  the  weight  of  water  at  G2^  pounds  per  cubic 
foot,  the  external  pressure  of  the  water  against  the  sides  of 
a  cofferdam  is  determined  by  the  following  rule  (see  Art. 
976,  Vol.  L): 

Rule. —  Tlie  pressure  upon  atiy  vertical  surface  due  to  the 
•weight  of  the  liquid  is  equal  to  the  weight  of  a  prism  of  the 
liquid  whose  base  has  the  same  area  as  the  vertical  surface ^ 


Fig.  465 


RAILROAD   CONSTRUCTION.  985 

and  whose  altitude  is  the  depth  of  the  center  of  gravity  of  the 
vertical  surface  beloiv  the  level  of  the  liquid. 

Cofferdams  are  really  retaining  walls,  which  were  fully 
described  in  Arts.  1486  to  1490,  inclusive,  and  the  forces 
acting  against  them  are  the  same,  though  somewhat  differ- 
ent in  application.  In  the  case  of  retaining  walls,  the  backing 
being  of  earth  or  broken  rock,  only  that  part  of  the  backing 
included  between  the  back  of  the  wall  and  the  line  of  natural 
slope,  extending  from  the  inner  foot  of  the  wall  upward  at  a 
slope  of  1^  horizontal  to  1  vertical,  exerts  any  pressure  upon 
the  wall.  In  the  case  of  water,  however,  the  particles,  hav- 
ing no  cohesive  force,  all  exert  pressure  against  the  dam. 
The  center  of  pressure  of  the  water,  like  the  center  of  pres- 
sure of  the  forces  acting  against  a  retaining  wall  with 
backing  level  with  its  top,  is  taken  at  one-third  of  the  depth 
of  the  water  above  the  bottom.  The  direction  of  the  water 
pressure  is  at  right  angles  to  the  face  of  the  cofferdam,  and 
the  moment  of  the  water  pressure  is  the  product  of  the 
pressure  found  by  the  above  rule  multiplied  by  one-third  the 
depth  of  the  water.  The  moment  of  the  resistance  of  the 
cofferdam,  that  is,  its  stability^  or  resistance  to  overturiiing, 
is  the  product  of  its  weight  multiplied  by  the  distance  from 
the  inner  toe  of  the  cofferdam  to  the  vertical  line  drawn 
from  the  center  of  gravity  of  the  cofferdam. 

Example. — If,  in  Fig.  465,  the  length  of  a  cofferdam  is  50  feet,  its 
height  7  feet,  its  thickness  4  feet,  and  the  'depth  of  water  6  feet,  {a) 
what  is  the  pressure  of  the  water  against  the  side  of  the  cofferdam  ? 
(b)  What  is  the  overturning  moment  of  the  water  pressure,  and  the 
resisting  moment  of  the  dam  ?  (r)  What  is  the  factor  of  safety  of 
the  dam  ? 

Solution.— («)  6  x  50  x  3  x  62.5  =  56,250  lb.,  the  pressure  against 
the  side  of  the  cofferdam.     Ans. 

ib)  In  determining  the  moments  of  the  water  pressure  and  of  the 
resistance  of  the  dam,  we  take  a  section  of  the  dam  1  foot  in  length. 
The  pressure  of  the  water  against  a  1-foot  section  of  the  cofferdam  is 
6  X  3  X  62.5  =  1,125  lb.  Its  center  of  pressure  is  at  one-third  the  depth, 
or  2  feet,  above  the  bottom.  The  moment  of  the  water  pressure  is, 
therefore,  1,125  X  2  =  2,250  lb.     Ans. 

Taking  the  weight  of  the  puddle  filling  at  130  pounds  per  cubic  foot. 


980  RAILROAD   CONSTRUCTION. 

we  have  for  the  weight  of  a  1-foot  section  7  X  4  X  120  =  3.360  lb.  The 
moment  of  resistance  of  the  dam  is  the  product  of  its  weight  by  the 
perpendicular  distance  from  the  inside  toe  of  the  dam  to  the  vertical 
line  from  the  center  of  gravity  of  the  section.  This  peVpendicular 
distance  is  2  feet.     3,360  X  2  =  6,720  lb.     Ans. 

(c)  This  moment  opposes  the  moment  of  the  water  pressure,  which 
we  found  to  be  2,250  lb.  The  factor  of  safety  of  the  dam  is,  therefore, 
the  quotient  of  6,720  h-  2,250  =  2.99,  nearly.     Ans. 

In  this  calculation  we  have  ignored  the  weight  of  the 
piles  and  timber  composing  the  cofferdam,  as  well  as  the 
resisting  power  of  the  piles.  These  would  considerably  in- 
crease the  factor  of  safety  of  the  dam.  The  water  pressure 
per  square  foot  upon  the  bottom  of  the  enclosed  area  will  be 
equal  to  the  depth  of  the  water  (G  feet)  multiplied  by  02.5, 
or  0  X  02:5  =  375  pounds.  This  pressure  is  resisted  by  the 
material  composing  the  bed  of  the  stream  and  the  sheet 
piling. 

If  the  bed  of  the  river  is  composed  of  compact  sand  or 
clay,  little  trouble  need  be  anticipated.  If,  however,  the 
bed  consists  of  loose  sand  and  gravel,  special  provision  must 
be  made  to  exclude  the  water. 

An  effective  device  used  by  French  engineers  is  the  fol- 
lowing (see  Fig.  400) :  Two  rows  of  piles  P,  P  are  firmly 
driven.  Wales  TF,  W  and  guides  G",  G  are  bolted  to  the 
piles.  A  row  of  close  piles  C  of  square  timber  is  driven 
and  bolted  or  pinned  to  the  outside  guide.  The  foimdation 
area  and  the  space  to  be  covered^  by  the  cofferdam  filling 
are  dredged  to  the  depth  of  3  or  4  feet  and  the  entire  pit 
filled  with  concrete.  Before  the  concrete  has  had  time  to 
set,  the  inside  row  D  of  close  piles  is  driven,  their  feet  pene- 
trating 2  feet  into  the  concrete.  The  clay  filling  is  deposited 
to  the  depth  of  one  foot  upon  the  fresh  concrete  and  rammed, 
so  there  may  be  a  perfect  connection  between  the  puddle 
and  the  concrete.  This  work  must  be  done  with  dispatch. 
The  remainder  may  be  deposited  more  gradually.  After 
sufficient  time  has  elapsed  to  allow  the  bed  of  concrete  to 
become  thoroughly  hardened,  the  water  is  pumped  out  of 
the  enclosure.     If  the  pressure  of  the  water  is  great  enough 


RAILROAD   CONSTRUCTION. 


987 


to  lift  the  concrete  foundation,  additional  weight  must  be 
added  to  keep  it  secure  until  the  weight  of  masonry  insures 
stability. 

P  JP 


Fig.  466. 

1555.  Pile  Foundations.  — When  the  river  bed  is 
composed  of  soft,  yielding  alluvium  extending  to  a  consider- 
able depth,  hut  underlaid  by  a  firm  soil  of  ample  depth,  a 
pile  foundation  is  commonly  adopted.  The  piles  should  not 
exceed  in  length  thirty  times  their  butt  diameter,  and 
should  be  cut  from  live  straight  trees.  Oak  piles  are  the 
most  durable  and  strongest;  rock  elm,  spruce,  and  yellow 
pine  are  of  about  equal  strength  and  durability.  The  out- 
line of  the  proposed  pier  will  to  some  measure  determine  the 
arrangement  of  the  piles,  but  the  general  arrangement  is 
always  the  same,  and  is  as  follows:  The  piles  are  driven  in 
rows,  spaced  not  less  than  two  and  a  half  feet,  center  to 
center,  and  cover  the  entire  foundation  area. 

In  some  special  cases  the  outside  row  of  piles  is  made 
double,  the  outer  piles  projecting  beyond  the  outlines  of  the 
pier.  The  calculation  of  the  bearing  power  of  piles  and  the 
various  methods  of  driving  are  fully  explained  in  succeeding 
pages.     The  piles,  after  being  thoroughly  driven,  are  sawed 


988  RAILROAD   CONSTRUCTION. 

off  at  a  uniform  level  at  a  suitable  depth  below  low  water 
level. 

A  general  plan  of  the  pile  foundation  and  the  masonry 
usually  adopted  for  bridge  piers  is  shown  in  Fig.  407.  The 
dimensions  of  the  foundation  from  center  to  center  of  out- 
side piles  are  width  9  feet  and  length  33  feet,  the  pier  being 
-*»  for  a  standard  double-track  roadway.  The  piles  are  cut  off 
4  feet  below  low  water.  A  timber  platform,  or  grillage, 
of  heavy  timbers  is  built  upon  the  piles,  to  receive  the 
foundation.  First,  a  course  of  cap  timbers  is  laid  crosswise 
upon  the  heads  of  the  piles.  The  caps  are  commonly  12  by 
14  inches,  and  notched  down  2  inches  upon  the  pile  heads, 
leaving  12  by  12  inches  of  solid  timber  above  the  piles. 
The  caps  extend  six  inches  outside  the  piles,  to  which  they 
are  fastened  with  1  inch  square  drift  bolts.  Care  must  be 
taken  that  the  tops  of  the  caps  are  on  a  uniform  level.  The 
second  course  of  timbers  is  stringers  12  by  14  inches  laid 
lengthwise  of  the  pier,  and  notched  down  2  inches  on  the 
caps  to  which  they  are  drift-bolted  at  each  intersection. 
They  are  laid  close  together,  forming  a  complete  flooring. 
A  third  course  of  12  by  12-inch  timbers  is  laid  at  right  angles 
to  the  stringers  to  which  they  are  securely  drift-bolted.  The 
top  of  the  grillage  should  be  at  least  1  foot  below  low  water. 
Upon  it  the  masonry  is  started. 

In  Fig.  467  A  shows  the  side  elevation  of  the  foundation 
and  pier;  B^  the  elevation  of  the  up-stream  end  of  the 
foundation  and  pier;  C,  the  arrangement  of  piles  in  the 
foundation,  and  Z>,  the  plan  of  the  pier.  The  courses  g  and 
h  are  the  coping  courses,  the  latter  forming  the  seat  upon 
which  the  bridge  rests.  The  foundation  piles  are  spaced  3 
feet  center  to  center.  The  grillage  of  timber  extends  on  all 
sides  12  inches  from  the  centers  of  the  outside  row  of  piles. 
The  first  course  of  masonry  is  laid  flush  with  the  outside  of 
the  grillage,  and  extends  on  all  sides  6  inches  beyond  the 
second  course.  The  second  course  projects  on  all  sides  6 
inches  beyond  the  main  body  of  the  pier. 

Beginning  with  the  third  course,  the  north  end  of  the 
pier  gradually  develops  into  a  conical-shaped  ice  breaker, 


RAILROAD   CONSTRUCTION. 


989 


and  in  construction  consists  of  the  intersection  of  a  cone 
with  a  wedge.     The  curve  of  intersection  is  shown  in  the 


hf—r 


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Fig.  467. 


elevation  by  the  curve  e /,  and  in  the  plan  by  the  curve  e'f. 
The  arrangement  of  the  stone  in  each  course  is  shown  in  the 


990  RAILROAD   CONSTRUCTION. 

elevation  A.  It  will  be  observed  that  in  no  instance  is  the 
bond  less  than  12  inches,  and  the  proportion  of  headers 
(stones  showing  their  short  side  at  the'  face  of  the  pier)  to 
stretchers  (stones  showing  their  long  side  at  the  face  of  the 
pier),  and  their  arrangement  is  such  as  to  form  one  compact 
mass  of  masonry. 

Where  there  is  a  rapid  current,  causing  frequent  changes 
of  channel,  as  is  the  case  with  many  Western  and  Southern 
rivers,  it  may  be  necessary  to  rip-rap  the  foundation.  This 
process  consists  of  depositing  stone  about  the  piles  to  a 
depth  of  4  or  5  feet,  the  deposit  extending  several  feet  be- 
yond the  piles  in  all  directions.  Any  action  of  the  current 
tending  to  undermine  the  foundation  is  promptly  checked 
by  the  rip-rap,  which  fills  any  cavity  worn  out  by  the 
current. 

In  making  working  drawings  for  bridge  piers,  the  arrange- 
ment of  the  stones  in  each  course  should  be  carefully  planned 
before  the  masonry  is  started.  If  only  two  or  three  courses 
are  planned  beforehand,  confusion  is  sure  to  follow.  By 
furnishing  quarrymen  with  complete  plans,  they  have  a 
wider  range  of  sizes,  and  will  be  enabled  to  take  better  ad- 
vantage of  the  stone  as  it  comes  from  the  quarry.  The 
probable  result  will  be  better  prices  and  prompter  delivery 
than  when  only  partial  plans  are  furnished. 

In  giving  dimensions  to  quarrymen,  no  allowance  is  made 
for  mortar  joints,  which  in  bridge  masonry  are  usually  one- 
half  inch  in  thickness.  When  the  given  dimension  is  taken 
from  an  angle  to  the  middle  of  a  joint,  the  stone  cutter  will 
deduct  one-fourth  inch  from  the  dimension  for  the  neat 
length  of  the  stone.  When  the  dimension  is  from  center  of 
joint  to  center  of  joint,  the  stone  cutter  deducts  one-half 
inch.  Detailed  plans  are  usually  sent  to  the  quarry  where 
the  stone  is  cut  to  dimension,  and  the  several  stones  for  each 
course  numbered,  the  courses  being  designated  as  Course 
A,  Course  B,  etc.,  or  in  some  other  way.  The  quarry  fore- 
man lays  out  the  work,  deducting  the  allowance  for  joints, 
and  the  stone  is  cut,  marked,  and  shipped  to  the  bridge  site 
in  shape  for  laying.      Stones  of  irregular  and  intricate  form 


RAILROAD   CONSTRUCTION.  991 

are  drawn  to  a  large  scale  of  from  1^  to  3  inches  to  the  foot, 
and  often  full-sized  drawings  are  made,  from  which  tem- 
plates of  sheet  zinc  are  cut  for  use  in  the  quarry. 

1556.  Stone    Suitable    for    Bridge    Masonry. — 

Stone  for  bridge  foundations  and  piers  must  be  free  from 
seams  and  defects  common  to  surface  stone.  Stones  con- 
taining free  iron  are  objectionable,  as  they  are  sure  to  be- 
come discolored  from  the  action  of  the  elements.  Granite 
is  to  be  preferred,  but  limestone,  hard  sandstone,  bluestone, 
and  marble  are  all  suitable.  In  ordinary  bridge  work,  the 
stone  is  laid  rock  face,  i.  e.,  with  undressed  faces,  and 
pitched  to  line  at  the  joints.  By  giving  the  corner  stones  a 
draft  of  two  inches,  i.  e.,  so.  as  to  show  two  inches  of 
dressed  surface  on  each  side  of  the  angle,  an  effect  of  much 
higher  finish  is  imparted  to  the  entire  work  at  compara- 
tively small  additional  cost. 

In  cutting  the  stone,  great  care  should  be  taken  to  make 
the  beds  even  and  the  stone  of  uniform  thickness  through- 
out, so  that  when  laid  the  beds  will  be  truly  horizontal.  In 
coursed  masonry  all  the  stones  in  each  course  have  the  same 
thickness  throughout.  A  variation  of  ^  inch  in  the  thick- 
ness of  the  stones  is  readily  detected,  even  by  an  unpractised 
eye.  All  mortar  used  in  bridge  building  should  be  prepared 
under  the  direction  of  a  competent  inspector,  and  under  no 
circumstances  used  after  setting  has  commenced. 

1 557.  Backing. — The  space  inclosed  by  the  face  stone 
is  usually  filled  with  a  less  expensive  material,  called  back- 
ing. In  large  piers,  concrete  is  much  used.  It  forms  a 
homogeneous  mass,  and  when  well  rammed,  as  it  always 
should  be,  fills  all  the  space  between  the  faces.  Rubble 
masonry  is  largely  used  for  backing,  and  in  laying,  care 
must  be  taken  to  secure  proper  bond,  especially  between  the 
backing  and  the  headers  which  reach  from  the  face  into  the 
body  of  the  pier.  Piers  erected  on  caisson  foundations  are, 
on  account  of  the  great  cost  of  sinking,  given  as  small 
dimensions  as  are  consistent  with  safety.  To  give  increased 
weight    and  strength  to  the  pier,   the   backing   is   cut   to 


992  RAILROAD   CONSTRUCTION. 

dimension,  so  that,  when  laid,  the  masonry  of  each  course, 
with  the  exception  of  the  joints,  forms  one  solid  mass  of 
stone. 

1558.  Coping. — The  top  course  of  masonry  forms  the 
coping  and  should  project  2  or  3  inches  over  the  main  body 
of  the  pier.  When  the  coping  is  of  two  courses,  the  projec- 
tion is  divided  between  them,  and  the  outer  edge  of  the  top 
course  is  beveled  to  an  amount  equal  to  the  total  projection. 
The  coping  courses  are  usually  dressed  stone,  which  adds 
greatly  to  the  finish  of  the  work. 

1559.  Pneumatic  Caisson  Foundations, — River 
beds  of  alluvium  extending  to  great  depth,  exposed  to  the 
scour  of  a  constantly  shifting  channel,  are  not  suited  to  pile 
foundations.  The  Mississippi  and  Missouri  rivers  are  stri- 
king examples  of  this  class.  A  firm  bearing  stratum  of  suf- 
ficient thickness  to  support  a  foundation  is  often  from  80  to 
100  feet  below  the  bed  of  the  river.  To  meet  these  condi- 
tions, caissons  built  of  heavy  timbers  are  sunk  either  to  bed 
rock  or  to  a  firm  stratum  of  clay  or  gravel  of  such  depth  as 
to  insure  permanent  safety. 

1560.  Test  Holes. — After  the  bridge  site  has  been 
determined  upon  and  before  the  bridge  plan  has  been  con- 
sidered in  detail,  test  holes  are  sunk  on  the  center  line  at 
intervals  of  from  100  to  200  feet,  to  determine  the  character 
of  the  material  forming  the  river  bed.  The  results  of  these 
examinations  will  largely  determine  the  lengths  of  the 
spans.  The  deeper  the  foundations  the  greater  will  be  the 
spans.  Having  determined  the  locations  of  piers,  test  holes 
are  sunk  at  each  pier  site,  in  sufficient  number  to  afford 
ample  knowledge  of  the  character  of  the  material  to  be  en- 
countered in  sinking  the  caisson.  A  complete  record  of 
each  test  hole  is  kept,  and  a  sectional  profile  platted,  showing 
the  specification. 

1561.  Modes  of  Sinking  Test  Holes.— Test  holes 
are  sunk  either  by  diamond  drills  or  by  driving  wrought- 
iron  pipe.     Piles  are  driven  to  support  a  platform,  upon 


RAILROAD   CONSTRUCTION. 


993 


which  is  placed  the  machinery  used  in  sinking  test  holes. 
Wrought-iron  pipe  is  commonly  adopted.  It  is  cut  in  sec- 
tions of  from  6  to  10  feet.  The  thread  on  pipe  and  couplings 
should  be  so  cut  that  when  coupled  the  ends  of  pipe  will 
abut  and  so  prevent  the  stripping  of  thread  which  is  liable 
to  result  from  the  repeated  blows  of  the  driver.  A  steel 
cap,  shown  in  Fig.  468,  is  screwed  to  the  top  of  the  pipe  to 
receive  the  blows  of  the  hammer. 


B 


JELO 


n 


C0 


Ei 


Fig.  469. 


Jk^. 


i»-A 


M  Water. 


1562.  The  Driver. — The  driver  is  constructed  on 
the  principle  of  the  pile  driver.  The  hammer  consists  of  a 
section  of  an  oak  or  other  hard  wood  tree,  from  9  to 
12  inches  in  diameter,  turned  to  a  uniform  size  and  fitted 
at  the  sides  with  steel  grooves,  through  which  pass  the 
guides  extending  the  full  length  of  the  leaders.  An  iron 
ring  is  fastened  in  the  top  of  the  hammer  to  which  is  at- 
tached the  rope  used  in  raising  the  hammer.  This  rope 
passes  through  a  common  pulley  with  wooden  sheave, 
which  is  fastened  with  fig.  468. 

rope  to  the  head  of  the 
leaders. 

The  leaders  are  of 
sufficient  length  to 
allow  the  hammer  a 
drop  of  4  feet  after  a 
new  section  has  been 
attached.  A  force  of 
4  or  5  men  is  required 
for  the  efficient  work- 
ing of  the  machine. 
In  sinking  into  the 
earth,  the  pipe  cuts  a 
section  equal  to  the 
inside  area  of  the  pipe. 
At  intervals  of  6  or  8 
feet  in  sinking,  and 
before  an  additional  section  is  attached,  the  pipe  is  cleared 
by  a  sand  pump. 


Silt. 


Sand. 


— *'-M 
Mil 


Coarse  Gravel. 


Fine  Gravel. 


41 

1" 

Fig.  471. 


Hard  Clay. 


994  RAILROAD   CONSTRUCTION. 

1563.  Tlie  Sand  Pump. — This  pump  consists  of  a 
section  of  iron  pipe  of  such  size  as  will  work  freely  inside 
the  pipe  being  driven.  Fig.  4G9  shows  longitudinal  section 
and  plan  of  sand  pump.  The  valve  A  consist^  of  a  ball  of 
iron  which,  rests  in  a  hollow  seat  and  acts  automatically. 
The  pump  is  lowered  into  the  pipe  by  means  of  a  rope 
attached  to  the  ball  B.  Water  is  poured  into  the  pipe  so 
that  the  contents  may  be  reduced  to  a  fluid  state.  As  the 
descending  pump  strikes  the  surface  of  the  water  in  the 
pipe,  the  valve  A  is  forced  upwards  and  the  water  and  sand 
pass  through  the  hole  C.  The  upper  part  of  the  valve 
chamber  D  is  ribbed,  as  shown  at  E.  This  arrangement 
confines  the  valve  and  at  the  same  time  allows  the  sand 
and  water  to  pass  into  the  chamber  F.  When  small  stones 
and  pebbles  enter  the  pipe  and  are  too  large  to  pass 
through  the  valve  opening,  they  must  be  broken  up  by  a 
churn  drill.  The  best  form  of  drill  is  one  with  a  cutting 
edge  or  bit  similar  to  that  commonly  used  in  steam  drills, 
shown  in  Fig.  470. 

The  drill  A  B  is  about  18  inches  in  length.  The  cutting 
edge  or  bit  A  is  in  the  form  of  a  cross  with  equal  arms.  To 
the  end  B  an  ordinary  pipe  coupling  is  attached.  The  body 
of  the  drill  is  of  gas  pipe  in  sections,  which  are  added  as  the 
hole  deepens.  The  bit  must  be  kept  sharp  and  the  couplings 
frequently  examined  that  no  stripping  of  thread  occurs, 
which  might  easily  result  in  the  loss  of  the  drill  and  prevent 
further  sinking.  Any  change  in  the  material  removed  from 
the  pipe  is  readily  detected,  and  the  depth  of  the  stratum  is 
determined  by  measuring  from  the  top  of  the  pipe. 

1 5<>4.  Record  of  Test  Holes. — A  good  form  for 
keeping  a  record  of  test  holes  is  given  in  Fig.  471,  which 
shows  a  sectional  profile,  giving  the  thickness  and  character 
of  each  stratum  passed  through.  The  profile  given  in  Fig. 
471  is  of  a  test  hole  driven  in  the  bed  of  a  river.  After  pass- 
ing through  different  strata  of  sand  and  gravel,  a  stratum 
of  hard  clay  is  encountered.  After  penetrating  9  feet  into 
this  clay,  any  further  sinking  is  unnecessary,  since  9  feet  of 


RAILROAD   CONSTRUCTION.  995 

hard  clay  will  afford  a  foundation  amply  strong  for  any 
ordinary  bridge. 

1565.  Dimensions  of  Caisson.  — The  depth  of  the 
foundation  stratum  will  affect  the  size  of  the  caisson  as  the 
faces  of  the  pier  are  battered,  increasing  the  size  of  the  plan 
as  the  depth  increases. 

For  example,  suppose  the  neat  dimensions  of  a  bridge  pier 
at  the  top  are  6  feet  by  30  feet,  and  all  the  faces  batter  at 
-^  inch  to  the  foot.  If  the  stratum  upon  which  the  caisson 
is  to  rest  is  93J  feet  below  the  top  of  the  pier,  and  the  height 
of  the  caisson  from  cutting  edge  to  deck  is  13  feet  4  inches, 
and  the  deck  is  to  extend  on  all  sides  6  inches  outside  of  the 
base  of  the  pier,  what  will  be  the  dimension  of  the  caisson 
floor  ?  As  the  pier  faces  batter  at  a  rate  of  -^  inch  to  the 
foot,  the  increase  in  each  dimension  will  be  as  many  inches 
as  the  pier  is  feet  in  height.  The  height  of  the  pier  is  93  ft. 
4  in.  —  13  ft.  4  in.  =  80  feet.  We,  therefore,  add  80  inches, 
or  6  feet  8  inches,  to  each  dimension  and  we  have  for  the 
base  of  the  pier,  length  30  feet  8  inches,  and  width  12  feet 
8  inches.  The  caisson  deck,  which  projects  6  inches  on  all 
sides  beyond  the  pier  base,  will  have  a  length  of  37  feet 
8  inches  and  a  width  of  13  feet  8  inches.  The  sides  of  the 
caisson  are  battered  on  all  sides  to  reduce  the  friction  of  the 
earth  against  them  during  the  progress  of  sinking.  The 
total  batter  on  each  side  is  12  inches.  This  batter  will  give 
to  the  base  of  the  caisson  the  following  dimensions,  viz., 
length  39  feet  8  inches,  and  width  15  feet  8  inches.  With 
the  general  dimensions  of  the  caisson  floor  as  determined 
above,  the  details  may  be  modified  to  suit  special  conditions. 

All  caisson  plans  must  meet  certain  requirements,  viz. : 
There  must  be  adequate  supply  shafts  for  admitting  men 
and  materials;  air  pipes  for  the  compressed  air,  and  a  con- 
crete shaft  by  means  of  which  the  concrete  used  in  sealing 
and  filling  the  caisson  may  be  conveyed  from  the  top  of  the 
masonry,  where  it  is  mixed,  to  the  caisson  ch-amber.  Supply 
shafts  are  of  boiler  iron  and  from  three  feet  to  four  feet  in 
diameter,   depending  upon  the  size  of  the   caisson.      The 


996 


RAILROAD   CONSTRUCTION. 


shafts  are  built  in  sections  of  from  four  to  eight  feet,  the 
connections  being  made  by  means  of  exterior  flanges,  which 
are  bolted  together. 


E  %=^^'^ 


c 


o'^^jr^ 


Q^ 


1 566.  Air  Locks. — The  shafts  (usually  two  in  num- 
ber) are  fitted  with  air  locks,  by  means  of  which  men  and 
materials  pass  from  the  outer  air  to 
the  caisson  chamber,  and  vice  versa^ 
without  the  escape  of  the  compressed 
air.  The  principle  upon  which  the 
air  lock  is  constructed  is  explained  in 
Fig.  472. 

A  is  the  air  lock  leading  to  the 
shaft  B^  which  extends  to  the  caisson 
chamber.  A  person  entering  the  cais- 
son finds  the  outer  door  in  th«  posi- 
tion C.  He  first  closes  the  air  cock 
D,  and  swings  the  door  shut,  the  door 
taking  the  position  E.  He  then  opens 
the  air  cock  F^  and  the  air  in  the  lock 
A  receives  the  pressure  of  the  air  in 
the  caisson,  forcing  the  door  E  firmly 
against  the  casing,  which  is  usually 
fitted  with  a  rubber  gasket,  making 
an  air-tight  joint.  The  pressure 
against  the  door  G  being  removed,  it 
opens  of  itself,  taking  the  position  H.  The  person  is  then 
in  direct  communication  with  the  caisson  chamber,  descend- 
ing to  it  by  means  of  the  ladder  K.  At  the  bottom  of  the 
shaft  is  another  door,  which  is  closed  when  the  air  lock  at 
the  surface  is  removed  for  adding  another  section  to  the 
shaft.  One  of  the  shafts  is  used  for  admitting  men  and 
tools,  the  other  for  removing  material.  The  air  lock  used 
in  removing  material  is  provided  with  a  windlass,  the  axle 
of  which  has  air-tight  bearings  and  extends  through  the 
sides  of  the  lock,  being  fitted  with  two  cranks  which  are 
operated  by  laborers.  Most  caissons  are  fitted  with  a  sand 
pipe,  by  means  of  which   the   pressure  of   the  air   in  the 


Fig.  472. 


RAILROAD   CONSTRUCTION.  997 

caisson  chamber  is  utilized  in  blowing  out  the  sand  or  any 
fine  material  excavated  in  sinking. 

1567.  Plan  of  Caisson. — A  general  plan  of  a  timber 
caisson  is  shown  in  Fig.  473,  in  which  G  represents  the 
plan ;  H  the  longitudinal  section,  and  K  the  cross-section. 
The  walls  6^  and  F,  enclosing  the  caisson  chamber,  are 
built  of  three  courses  of  timber  12'  X  Vl'  square.  The 
outer  and  inner  courses  consist  of  superimposed  horizontal 
timbers  extending  the  full  length  and  width  of  the  caisson. 
The  inner  course  of  timbers  is  laid  in  an  upright  position, 
and  extends  to  within  1  foot  of  the  top  of  the  caisson  deck. 
The  timbers  in  the  walls  are  securely  bolted  together  with 
drift  bolts,  each  bolt  passing  entirely  through  two  timbers 
and  penetrating  fully  6  inches  into  the  third.  As  the  tim- 
bers are  laid,  they  are  poured  with  hot  coal  tar  or  pitch. 
At  frequent  intervals,  the  horizontal  layers  of  timber  are 
bolted  to  the  upright  timbers  with  screw  bolts.  The  bolt 
heads  must  be  countersunk  and  the  sockets  filled  with  pitch. 
Rubber  washers  are  used  to  insure  tight  joints. 

The  cutting  edge  a  \s  oi  \  inch  boiler  plate,  8  inches  in 
width,  and  backed  by  4-inch  oak  plank.  The  walls  above 
the  cutting  edge  increase  in  thickness  with  each  course  of 
timber,  attaining  their  full  thickness  of  3  feet  in  the  third 
course.  When  the  caisson  is  of  great  size,  longitudinal 
division  walls  are  built  dividing  the  caisson  chamber  into 
compartments.  Openings  are  made  in  these  walls  to  admit 
of  free  communication  between  the  various  compartments. 
The  caisson  shown  in  Fig.  473  has  not  sufficient  breadth  to 
require  any  interior  division  walls.  Struts  V  of  12'  X  12' 
timber  placed  at  intervals  of  about  8  feet  insure  lateral 
stiffness,  and  2-inch  iron  tie-rods  Z  fitted  with  turnbuckles 
prevent  the  walls  from  spreading. 

The  deck  consists  of  six  courses  of  12'  X  12'  timbers  so 
laid  as  to  render  the  chamber  as  nearly  air-tight  as  possi- 
ble, and  give  the  greatest  possible  stiffness  and  strength  to 
the  structure.  The  first  course  A  forms  the  ceiling  of  the 
chamber,  the    timbers   extending   the  entire  width  of   the 


998 


RAILROAD   CONSTRUCTION. 


RAILROAD   CONSTRUCTION.  999 

caisson.  A  layer  of  zinc  enclosed  between  two  layers  of 
felt  is  laid  over  the  entire  ceiling  course  and  ceiling,  and 
floated  with  pitch.  The  timbers  are  laid  close,  with  joints 
filled  with  pitch  and  fastened  to  the  walls  with  heavy  anchor 
bolts.  Course  B  is  laid  diagonally  to  course  A  and  bolted 
to  it,  a  share  of  the  bolts  extending  into  the  side  walls. 
The  diagonals  stop  at  6^  feet  from  the  ends  of  the  caisson. 
The  balance  of  the  course  is  laid  longitudinally,  with  the 
alternate  timbers  passing  between  the  uprights  and  extend- 
ing to  the  outside  sheathing  of  the  caisson.  Course  C  is 
laid  transversely ;  course  D  diagonally,  the  diagonal  timbers 
being  at  right  angles  to  those  in  course  B^  and  stopping  at 
^\  feet  from  the  ends  of  the  caisson,  as  in  course  B,  and  the 
balance  of  the  course  laid  longitudinally,  as  in  that  course. 
Course  E  is  laid  transversely.  Course  /%  forming  the  deck 
of  the  caisson,  is  laid  transversely,  and  the  masonry  is 
started  upon  it. 

An  adz  is  used  to  give  to  the  outside  walls  their  proper 
batter.  They  are  sheathed  with  4-inch  plank,  tongued  and 
grooved,  the  joints  of  which  are  filled  with  either  hot  coal 
tar  or  pitch.  The  sheathing  affords  a  smooth  outside  sur- 
face, which  greatly  reduces  the  friction  of  the  earth  against 
the  sides  of  the  caisson.  The  timbers  forming  the  inside 
walls  and  ceiling  of  the  caisson  chamber  are  first  thoroughly 
calked  and  then  covered  with  a  layer  of  1^-inch  hemlock  or 
spruce.  This  surface  is  then  covered  with  tarred  paper  and 
a  second  layer  of  1^-inch  matched  spruce  boards,  with  leaded 
joints.  L  and  M  are  supply  shafts — L  for  admitting  men 
and  tools,  and  M  for  removing  excavated  materials.  N  is 
a  shaft  for  admitting  concrete  for  sealing.  The  small  shaft 
shown  between  L  and  N  is  an  air  pipe  for  conveying  air 
from  the  compressor  to  the  caisson  chamber.  The  pipes  /*, 
Q,  and  R  are  sand  pipes,  by  means  of  which  sand  and  other 
fine  material  encountered  in  sinking  may  be  forced  out  of 
the  chamber  by  compressed  air. 

The  air  lock  connecting  with  shaft  L  is  shown  in  plan  at 
S,  and  in  elevation  at  T.  It  is  fitted  with  exterior  flanges, 
which   fit    the    flanges   of    the   sections   of    the    shaft    L. 


1000  RAILROAD   CONSTRUCTION. 

Ordinarily  the  air  lock  Tis  used.  When,  however, the  masonry 
has  reached  the  height  of  the  air  lock  T,  the  air  lock  d  at 
the  foot  of  shaft  L  is  closed.  The  air  lock  T  is  then  re- 
moved, another  section  of  shafting  added,  and  the  lock  again 
placed  in  position.  The  air  lock  d  is  then  opened  and  the 
door  fastened  to  the  caisson  ceiling.  The  air  lock  for  shaft 
Mis  placed  within  the  caisson  chamber  at  X.  This  shaft  is 
used  in  hoisting  excavated  material,  which  is  placed  in  buck- 
ets and  raised  by  a  windlass  placed  on  the  top  of  the  masonry. 
The  buckets  are  filled  and  placed  in  the  lock.  Connection 
with  the  caisson  chamber  is  then  cut  off,  and  the  bucket 
hoisted  to  the  surface. 

The  caisson  is  usually  built  near  the  shore,  and  when 
completed  it  is  floated  to  the  pier  site,  where  it  is  held  in 
position  by  strong  hawsers  fastened  to  cluster  piles.  The 
masonry  is  then  started  on  the  caisson  deck,  and  the  pres- 
sure of  the  air  increased  as  the  weight  of  the  masonry  causes 
the  caisson  to  sink.  As  the  caisson  approaches  the  bed  of 
the  stream,  it  must  be  accurately  located,  so  that  when 
grounded  it  will  take  the  exact  position  prescribed  for  it  in 
the  plan.  Though  of  great  weight,  so  long  as  the  caisson 
floats,  its  position  may  be  readily  changed,  but,  once 
grounded,  only  a  slight  change  of  position  is  possible. 

1568.  Sinking  tlie  Caisson. — Once  grounded  in  the 
proper  position,  the  sinking  of  the  caisson  should  be  pros- 
ecuted with  vigor.  Since  all  excavated  material  must  pass 
through  an  air  lock,  the  process  of  hoisting  it  to  the  surface 
is  necessarily  slow. 

After  the  enclosed  area  has  been  excavated  to  a  depth  of 
from  12  to  18  inches,  the  cutting  edge  of  the  caisson  is  un- 
dermined to  an  equal  depth.  The  air  pressure  is  then  re- 
laxed, and  the  weight  of  the  caisson,  together  with  its  load 
of  masonry,  causes  it  to  sink  until  it  again  rests  on  a  firm 
footing.  When  the  excavated  material  is  sand,  it  is  usually 
removed  from  the  chamber  by  the  sand  pipe.  To  effect  this 
a  piece  of  flexible  hose  is  attached  at  one  end  to  the  air  pipe 
near  the  ceiling.    The  other  end  is  fitted  with  a  shear  valve. 


RAILROAD   CONSTRUCTION.  1001 

The  sand  is  shoveled  into  piles,  and  the  hose  brought  into 
direct  contact  with  it.  The  valve  is  then  opened,  and  the 
air  pressure  forces  the  sand  through  the  hose  and  air  pipe 
to  the  surface,  where  another  piece  of  hose  is  attached,  which 
carries  the  sand  outside  the  masonry.  When  rock  is  en- 
countered it  is  broken  by  blasting,  and  removed  in  buckets 
through  the  shaft.  The  rock  encountered  in  sinking  the 
caisson  of  the  Washington  bridge  at  New  York  was  drilled 
with  an  air  drill,  the  compressed  air  being  furnished  by  the 
same  plant  which  supplied  compressed  air  to  the  caisson. 
Dynamite  was  used  to  break  the  rock.  The  caisson  was 
lighted  by  electricity  generated  by  a  small  dynamo  stationed 
in  the  compressor  house. 

When  the  caisson  is  situated  at  a  distance  from  the  shore, 
the  compressor  plant  is  placed  on  a  boat  securely  anchored 
at  a  short  distance  from  the  caisson. 

1569.  To  Determine  the  Air  Pressure  in  tlie 
Caisson. — The  air  pressure  in  a  caisson  must  be  sufficient 
to  resist  two  external  forces — the  one  due  to  the  atmospheric 
pressure  and  the  other  due  to  the  pressure  of  the  water. 
The  atmospheric  pressure  is  taken  at  15  pounds  per  square 
inch.  The  pressure  of  the  water  in  pounds  per  square  inch 
is  found  by  multiplying  the  depth  by  .434.  The  sum  of  the 
two  pressures  will  be  the  amount  of  the  air  pressure  which 
must  be  maintained  in  the  caisson  in  order  to  exclude  the 
water. 

Example. — At  a  depth  of  50  feet,  what  will  be  the  working  pressure 
in  a  caisson  ? 

Solution.— .434  x  50  =  21.7;  21.7  +  15  =  36.7  lb.     Ans. 

1570.  Sealing  tlie  Caisson. — When  the  caisson 
reaches  a  secure  foundation  the  process  of  sealing  at  once 
follows.  This  process  consists  in  filling  the  entire  chamber 
with  concrete.  The  concrete  is  mixed  on  top  of  the  pier  and 
conveyed  to  the  caisson  chamber  through  the  concrete  shaft. 
This  shaft  or  pipe  is  from  12  to  18  inches  in  diameter  and 
fitted  at  both  top  and  bottom  with  an  air-tight  door.  While 
charging  the  pipe  with  concrete  the  bottom  door  is  closed. 


1002  RAILROAD   CONSTRUCTION. 

When  the  pipe  is  full  the  surface  door  is  shut,  the  bottom 
door  opened,  and  the  contents  of  the  pipe  is  discharged  with- 
in the  chamber.  The  concrete  is  then  carried  in  wheelbar- 
rows to  the  extremities  of  the  chamber,  which  are  first  filled, 
the  concrete  being  forced  into  every  cavity.  The  chamber 
is  completely  filled  from  floor  to  ceiling,  the  space  about  the 
concrete  pipe  and  shaft  being  left  until  the  last.  When  the 
space  has  become  too  small  to  work  in,  the  workmen  leave 
the  chamber,  and  the  remaining  space  is  readily  filled  with 
material  from  the  top  of  the  shaft. 


PILE    WORK. 

1571.  Pile  Driving. — There  is  no  subject  connected 
with  construction  upon  which  there  is  so  little  accurate 
knowledge.  This  is  partly  accounted  for  by  the  fact  that 
the  material  into  which  piles  are  driven  lies  below  the  sur- 
face of  the  ground,  and  exact  knowledge  of  it  is  difficult  to 
obtain. 

Nor  will  a  knowledge  of  the  material  into  which  the  piles 
are  driven  enable  the  engineer  to  accurately  measure  the 
forces  which  give  to  the  pile  its  bearing  power. 

The  bearing  power  of  a  pile  depends  upon  two  things,  viz. : 
first,  the  strength  of  the  pile  considered  as  a  column,  and, 
.f^^<7«^, the  friction  of  the  ground  against  the  sides  of  the  pile. 

1572.  Pile-Driving  Formulas. ^A  number  of  for- 
mulas for  guiding  engineers  in  pile  work  have  been  prepared 
by  eminent  engineers.  Most  of  these  formulas  are  more  or 
less  complicated.  Some  employ  values  which  are  difficult  to 
obtain  and  are  not  suited  to  practical  constructors.  The  fol- 
lowing formula,  published  by  the  "  Engineering  News,"  and 
known  as  the  Engineering  Nezas'  formnla,  is  very  simple, 
andean  be  safely  followed  under  all  circumstances: 

L  =  '^  (109.) 

in  which  L  —  safe  ioadm  tons,  pounds,  or  other  units;  u>  = 
weight  of  hammer  in  same  unit;  /i  =  fall  of  hammer  in  feet; 
5  =  penetration  of  pile  in  inches  at  the  last  blow,  and  as- 


RAILROAD   CONSTRUCTION.  1003 

sumed  to  be  sensible  at  an  approximately  uniform  rate 
(and  head  of  pile  in  good  condition,  i.  e. ,  not  split  or  broomed). 
This  formula  gives  a  factor  of  safety  of  6,  i.  e.,  the  actual 
load  which  the  pile  can  safely  carry  is  only  ^  of  its  total 
bearing  power,  and  is  applicable  to  all  forms  of  raflroad  con- 
struction from  an  ordinary  trestle  to  a  drawbridge  pier  or 
turntable  foundation. 

1573.  Methods  of  Driving. — There  are  six  methods 
of  driving  piles. 

First  Method. — Ordinary  method,  in  which  a  hammer 
weighing  from  2,000  to  3,000  pounds  or  more  is  dropped 
from  a  height  of  from  20  to  30  feet,  falling  free  upon  the 
head  of  the  pile.  Intervals  between  blows,  from  5  to  20 
seconds. 

Second  Method. — The  same  as  first,  except  that  the  ham- 
mer is  attached  to  rope  which  is  slacked  on  the  winding 
drum,  allowing  the  hammer  to  fall.  This  method  permits 
more  rapid  blows  than  the  first  method,  but  there  is  a  loss  of 
from  20  to  40  per  cent,  of  the  force  of  the  blow,  caused  by 
the  friction  of  rope  on  the  drum  and  the  hoisting  sheave.  It 
also  admits  of  deliberate  deception  on  the  part  of  the  con- 
tractor, who  can  check  the  fall  of  the  hammer  by  the  friction 
brake,  delivering  blows  of  not  half  the  force  which  the 
amount  of  fall  would  indicate.  This  method  is,  however, 
very  convenient  and  fair  if  properly  used. 

Third  Method. — By  Water  Jet.  In  this  a  stream  of 
water  under  pressure  is  ejected  at  or  near  the  point  of  the 
pile,  the  water  rising  along  the  sides  of  the  pile  and  remov- 
ing nearly  all  the  end  and  side  resistance,  so  that  the  pile 
sinks  by  its  own  weight,  though  sometimes  extra  pressure  is 
added.  This  method  is  specially  adapted  to  compact  sandy 
soils,  and  is  often  efficacious  where  all  other  methods  fail. 

Fourth  Method. — By  Direct  Pressure  of  a  Constant 
Weiglit.  This  method  is  applicable  to  soils  of  a  wet  silty 
nature  (practically  saturated  with  water). 

This  method  is  much  employed  in  dock  building  at  and  in 
the  neighborhood  of  New  York.     The  method  is  sometimes 


1004  RAILROAD   CONSTRUCTION. 

knovina.s  pulling  down  piles.  In  the  mud  of  the  Hudson 
river,  it  is  almost  impossible  to  drive  a  pile  by  ordinary 
methods,  and  the  process  oi fulling  is  employed  by  placing 
part  of  the  weight  of  a  scow  as  an  insistent  weight  upon  the 
pile,  which  sinks  it  into  the  mud. 

Fifth  Method. — By   Nasmyth   or   Other   Steam   Pile 

Drivers.  In  this  the  hammer  weighs  from  3,000  to  5,000 
pounds.  The  fall  is  short,  usually  about  3  feet,  but  the  blows 
are  correspondingly  rapid,  usually  about  GO  per  minute. 
Otherwise  the  principle  is  the  same  as  Method  1. 

Sixth   Method. — By    Gunpowder    Pile    Driver.        In 

this  each  blow  is  a  double  one,  the  first  caused  by  the  fall  of 
the  hammer,  and  the  second  by  the  explosion  of  the  powder 
on  the  head  of  the  pile,  which  in  turn  throws  the  hammer 
upwards.  By  this  method,  there  is  scarcely  any  intermission 
in  the  downward  movement  of  the  pile. 

1574.  The  Striking   Force  of  the  Hammer. — In 

calculating  the  striking  force  of  the  hammer,  the  resistance 
of  the  air  and  friction  is  not  regarded.  The  leaders,  i.  e., 
the  upright  timbers  between  which  the  hammer  works,  are 
supposed  to  be  vertical,  and  the  hammer,  held  in  place  by 
well  lubricated  guides,  falls  about  as  freely  as  though  uncon- 
fined.  Thus,  a  3,000-pound  hammer  falling  a  height  of  20 
feet  will  strike  a  blow  of  3,000  X  20  =  00,000  ft. -lb. 

1575.  Interval  of  Time  Between  Blows. — Blows 
should  be  delivered  at  as  nearly  uniform  intervals  as  possible, 
and  the  driving  continued  until  the  pile  is  completely  driven. 
The  effect  of  an  interval  of  rest  of  even  a  few  minutes  is  to 
permit  the  ground  to  settle  about  the  pile,  thereby  greatly 
increasing  its  resistance  to  driving.  This  effect  is  most 
marked  in  fine,  soft,  and  wet  earth,  and  least  in  coarse  gravel 
and  sand.  When  driving  in  soft,  wet  soils,  the  penetration 
from  last  blow  should  not  be  taken  for  value  of  S,  but  after 
allowing  an  interval  of  rest,  depending  upon  the  action  of 
the  material  upon  the  piles,  the  mean  penetration  from 
several  blows  should  be  taken. 


RAILROAD   CONSTRUCTION. 


1005 


1576.  Effects, of  Broomed  Heads. — According  to 
best  authorities,  a  broomed  head  will  destroy  from  half  to 
three-quarters  of  the  effect  of  a  blow,  even  where  the  broom- 
ing is  not  more  than  half-inch  deep.  To  apply  a  formula, 
it  will  be  necessary  to  adz  or  saw  off  the  head  of  the 
pile  so  as  to  secure  the  full  force  of  the  hammer.  Apply  the 
formula  to  several  cases,  the  average  result  of  which  may  be 
depended  upon. 

1 577.  Effect  of  Driving  with  Hammer  Attached 
to  Rope. — The  common  practice  of  driving  with  hammer 
attached  to  rope  is  to  be  condemned.  The  force  necessary 
to  uncoil  the  rope  from  the  drum  and  the  friction  of  rope  on 
hoisting  sheave  rob  the  blow  of  at  least  one-fourth  of  its 
force.  In  an  actual  case  in  practice,  a  pile  penetrated  0.5 
foot  with  a  40-foot  fall  of  a  2,470  pound  hammer  with  line 
attached  to  hammer  and  slacked  on  drum;  it  penetrated 
0.7  foot  when  hammer  was  allowed  to  fall  free,  the  gain  in 
penetration  from  a  free  fall  of  hammer  being  40  per  cent, 
greater  than  when  the  hammer  was  attached  to  a  rope. 

1578.  Pile  Shoes. — In  cases  where  piles  are  to  be 
driven  through  a  stratum  of  boulders,  old  cribwork,  or  any 
substance  offering  great  resistance  to  driving,  resort 
is  frequently  had  to  shoeing  the  piles  with  either  cast  or 
wrought  iron.  Common  forms  of  shoes  are  shown  in  Figs.  474 
and  475.     The  shoe  in  Fig.  474  is  of  wrought  iron,  the  point 


Fig.  474.     Fig.  475. 


Fig.  476. 


Fig.  477. 


being  fastened  to  the  pile  by  spikes  through  the  strap  s.   The 
shoe  in  Fig.  475  is  an  inverted  cone  of  cast  iron.     The  bolt 


1006  RAILROAD   CONSTRUCTION. 

«,  which  fastens  the  shoe  to  the  pile,  is  of  wrought  iron,  the 
cone  being  cast  around  it.  The  fiat  base  of  the  cone  affords 
a  good  bearing  for  the  foot  of  the  pile.  The  practice  of 
shoeing  piles  has  of  late  years  fallen  into  disuse.  In  a  great 
many  instances  where  shoes  have  failed,  piles  cut  off  square 
have  driven  fairly  well.  Shod  or  pointed  piles  are  liable  to 
cant  or  drive  at  an  angle.  In  average  ground  a  pile  cut  off 
square  at  the  point  will  drive  better,  truer,  and  almost  as 
rapidly  as  when  pointed.  There  are,  however,  situations 
where  either  shoeing  or  pointing  is  absolutely  necessary. 

1 579.  Pile  Hoops. — To  prevent  the  pile  from  splitting 
while  driving,  the  head  is  surrounded  by  an  iron  hoop  from 
one-half  to  one  inch  thick  and  from  1^  to  3  inches  wide, 
as  shown  in  Fig.  47G.  They  are,  however,  an  uncertain 
security,  especially  in  hard  driving,  when  often  the  pile 
splits  below  the  hoop  and  bulges  to  such  an  extent  that  it 
must  be  cut  off  before  the  driving  can  be  continued. 

1580.  Slight  Penetration  Often  Indicates  Poor 
Driving. — When  the  penetration  caused  by  a  high  fall  of 
a  heavy  hammer  is  less  than  one-fourth  inch  with  oak  or 
one-half  inch  with  soft  wood  piles,  there  is  danger  of  over 
driving.     A  common  mode  of  failure  is  shown  in  Fig.  477. 

1581.  Spacing  Piles. — Bearing  Piles,  i.  e.,  those 
used  for  foundations,  should  not  be  spaced  less  than  three 
feet  center  to  center;  those  spaced  less  than  2^  feet  are 
worse  than  wasted.  Where  piles  are  overcrowded,  the  soil 
either  becomes  churned  to  a  liquid  mass  or  so  compressed 
that  those  already  driven  are  forced  upwards  while  others 
are  being  driven.  This  effect  sometimes  occurs  where  the 
surface  soil  is  underlaid  with  quicksand  or  soil  of  a  buoyant 
nature,  even  where  there  is  no  overcrowding.  A  remedy 
for  this  trouble  is  often  found  in  driving  piles  with  the  large 
end  or  top  downwards.  Where  a  considerable  area  is  to  be 
piled,  those  at  the  center  should  be  driven  first,  then 
working  towards  the  outside  of  the  area.  Where  the  reverse 
order  is  used,  the  soil  of  the  enclosed  area  often  becomes  so 
compressed  that  piles  can  not  penetrate  it. 


RAILROAD   CONSTRUCTION. 


1007 


1582.  Computing  Loads.  —  Calling  the  average 
weight  of  masonry  two  tons  per  cubic  yard,  piles  spaced 
three  feet  center  to  center  will  carry  a  wall  of  masonry  from 
50  to  75  feet  in  height.  Piles  spaced  24  feet  center  to 
center  will  support  a  wall  of  masonry  from  75  to  100  feet  in 
height.  Greater  loads  are  not  warranted  by  good  practice. 
Where  a  greater  mass  of  masonry  is  required,  the  founda- 
tions should  be  stepped  out  so  as  to  admit  another  row  of 
piles,  thus  distributing  the  pressure  over  a  greater  surface. 

Example. — A  double  row  of  foundation  piles  carries  an  18-inch 
masonry  wall.  The  piles  are  spaced  3  feet  center  to  center,  i.  e.,  as 
shown  in  Fig.  478,  and  driven  with  a 
1,000-pound  hammer,  until  a  fall  of  15 
feet  causes  a  penetration  of  one-fourth 
inch.  What  height  of  wall  can  be  safely 
carried  by  the  piles  ? 

Solution. — By   formula   109,   L  — 

-^ — -,  we  have  Z,  safe  load  in  tons;  w, 

weight  of  hammer  =  .5  ton;  h,  height 
of  fall  of  hammer  =  15  feet;  5,  last  pene- 
tration =  \  inch.  Substituting  these 
values  in    the   formula,    we   have   L  =  fig.  478. 

— ^ —  =  T^o^^  ^^  tons,  i.e.,  each  pile  will  safely  support  13  tons. 

.^5  -f-  1  l./wO 

Each  yard  in  length  of  the  wall  is  supported  by  two  piles,   which 

together  can  safely  carry  24  tons.      Taking  the  average  weight  of 

masonry  at  two  tons  per  cubic  yard,  such  a  foundation  would  support 

an  18-inch  wall  72  feet  in  height.     Ans. 

Modern  depot  buildings  often  carry  roof  trusses,  which 
tax  foundation  piles  to  their  safe  limit. 

1583.  Trestle  Loads. — In  computing  loads  for  pile 
trestles  it  is  not  too  great  an  allowance  to  assume  that  the 
entire  weight  of  the  driving  wheel  base  falls  upon  each 
bent,  or  row  of  piles,  in  succession.  Suppose,  for  example, 
a  bent  of  four  piles  is  driven  in  building  a  trestle  for  heavy 
railroad  traffic.  In  driving,  a  hammer  weighing  3,000 
pounds  is  given  a  free  fall  of  30  feet,  and  suppose  the  average 
penetration  for  the  last  three  blows  for  the  different  piles  is 
as  follows: 


1008  RAILROAD   CONSTRUCTION. 

First  pile,  ^  inch;  second  pile,  |  inch;  third  pile,  f  inch; 
fourth  pile,  f  inch. 

Applying  formula  109,  L  =  c-  i   i  >  ^^  have 

Of    1     A(      1.     -1      r      2X1.5X30      90  tons      ^^  ^  ^ 
Safe  load  for  1  st  pile,  L  = =  — — - —  =  60. 0  tons. 

.  0  ~|~  X  i.  0 

cf    1     A(      ^A      -1      r      2X1.5X30      90  tons      ^_  ^ 
Safe  load  for  2d   pile,  L  =  —  —  =  =  G5. 5  tons. 

.  O  i  O  ~\~  X  1.  o  /  o 

„    -    ,      .  ,      _  ,      .,      J.      2  X  1.5  X  30      90  tons      _.   .  ^ 
Safe  load  for  3d  pile,  L  =  — ^,^   ,   ^ —  =    ^  ^.^^    =  5o.  4  tons. 

.bJio  -|-  1  l.u«o 

o  i:    1     /If      ^^u     -1      r      2X1.5X30      90  tons      „^    . 
Safe  load  for  4th  pile,  L  ■= —  =  — — — —  =  51.4  tons. 

Total  safe  load  for  four  piles 232.3  tons. 

Taking  the  weight  on  wheel  base  of  a  consolidation  engine 
at  48  tons,  which  load  each  bent  must  successively  carry,  and 
dividing  the  combined  safe  load  of  the  four  piles,  viz.,  232.3 
tons,  by  48  tons,  the  weight  on  the  wheel  base,  we  have  a 
quotient  of  4.84,  i.  e.,  the  bent  is  able  to  safely  carry  4.84 
times  as  great  a  load  as  it  will  ever  be  required  to  carry. 
The  above  values  of  JS"  are  much  smaller  than  can  be  obtained 
in  many  soils.  Often  the  penetration  from  the  last  blow  is 
several  inches.  If,  however,  the  piles  are  allowed  to  stand 
24  hours  and  the  earth  to  settle  firmly  about  them  before 
being  tested  with  the  hammer,  it  will  usually  require  two  or 
three  heavy  blows  to  start  them.  Supposing  the  average 
penetration  for  the  last  three  blows  on  the  above  given 
piles  had  been,  respectively,  2  in.,  3  in.,  3^  in.,  and  2J  in., 
the  safe  loads  would  have  been  the  following,  viz.,  30  tons, 
22.5  tons,  20  tons,  and  24  tons,  and  the  aggregate  safe  load 
90.5  tons,  which,  divided  by  48  tons,  the  weight  on  wheel 
base  of  locomotive,  gives  a  quotient  of  2.00 -[- ,  i-  e.,  the 
trestle  can  safely  carry  twice  as  great  a  load  as  will  ever  be 
required  of  it. 

1584.  Piles  Acting  as  Columns. — Piles  penetrating 
through  soft,  yielding  material  into  a  comparatively  hard, 
unyielding  material  act  as  columns,  and  should  be  given  a 


RAILROAD   CONSTRUCTION.  1009 

factor  of  safety  not  less  than  six.  Assuming  the  weight  of 
hammer  at  3,000  pounds  and  the  fall  20  feet,  we  have  a  blow 
of  3,000  X  20  =  00,000  ft. -lb.,  and  for  penetration  of  1  in., 
2  in.,  3  in.,  4  in.,  5  in.,  and  6  in.,  the  safe  load  in  pounds  by 
our  formula  is  00,000,  40,000,  30,000,  24,000,  20,000,  17,143 
lb.,  respectively,  which  is  about  ^  of  the  ultimate  breaking 
load  of  a  10-inch  column  of  wood  of  a  height  of  8  feet,  14 
feet,  18  feet,  21  feet,  24  feet,  and  20  feet,  respectively.  Where 
the  length  of  the  column  without  side  support  is  greater 
than  this  and  the  safe  load  by  the  formula  is  less,  in  the 
same  proportion  will  the  safe  load  given  by  the  formula  ex- 
ceed the  safe  load  of  the  column,  i.  e.,  the  safe  load  indi- 
cated by  the  penetration  will  be  in  excess  of  the  load  which 
an  unsupported  column  can  carry. 

1585.  Pile-Driving  Machines. — Pile-driving  ma- 
chines are  of  two  general  classes,  viz.,  land  machines  and 
floating  machines.  In  both  classes  the  framework  of 
the  pile  driver  is  essentially  the  same.  This  framework 
consists  of  the  upright  timbers  called  the  guides  or  leaders 
which  hold  the  pile  in  position  and  between  which  the  ham- 
mer rises  and  falls,  the  wooden  bracing  of  the  leaders,  and 
the  iron  stayrods  for  the  same. 

The  machinery  for  hoisting  the  hammer  may  be  either  a 
simple  crab-winch  or  a  stationary  engine,  or  horse  power 
may  be  used.  For  all  important  modern  work  a  hoisting 
engine  is  used.  The  land  machine  (see  Fig.  479)  rests  on 
longitudinal  sills  A,  A,  which  in  turn  rest  on  rollers^.  The 
hoisting  machinery,  contained  in  the  house  C,  and  the  coal 
and  water  supply  D  and  £  are  well  to  the  rear  of  the  frame- 
work. When  a  row  of  piles  is  driven,  they  are  cut  off  at  a 
fixed  elevation  and  capped  and  temporary  or  permanent 
stringers  laid.  The  pile  driver  is  then  moved  forwards  on 
its  rollers,  the  leaders  F  projecting  far  enough  beyond  the 
last  bent  to  reach  the  line  of  the  next  row  of  piles.  The 
engine,  boiler,  coal  and  water  supply,  resting  on  the  rear  end 
of  the  framework  of  the  machine,  serve  as  a  counterweight. 
The  side  braces  6",  G  extend  nearly  to  the  heads  of  the 


1010 


RAILROAD   CONSTRUCTION. 


leaders,  and  foot  upon  the  cross  timber  //,  where  they  are 
securely  braced  with  timber  knees  A',  K.  The  back  braces 
Z,  J/,  and  N  are  bolted  at  top  to  the  leaders  and  at  bottom 
to  the  sills  O  and  /*and  to  the  cross  timber  Q.  The  main 
back  braces  L  are  fitted  with  rounds,  forming  a  ladder,  by 


Fig.  479. 


means  of  which  ascent  is  made  to  the  hammer  sheave  R. 
Stayrods  5  and  7",  fitted  with  turnbuckles,  extend  from 
the  heads  of  the  leaders  to  anchorages  in  the  sills  at  the 
rear  end  of  the  framework.  The  hammer  rope  ^^  winds  on 
a  drum  not  shown  in  the  drawing.     The  brackets  Fand  W 


RAILROAD   CONSTRUCTION.  1011 

support  cross-bars  upon  which  the  hammer  rests  when  not 
working.  The  sizes  of  the  timbers  will  depend  upon  the 
character  of  the  work  to  be  done  and  upon  the  length  of  the 
piles  to  be  driven. 

The  floating  machine  (see  Fig.  480)  is  carried  on  a  power- 
fully built  scow  A  of  light  draught.  The  machine  shown  is 
of  the  latest  model,  and  the  heaviest  in  New  York  harbor. 
The  hull  is  56  feet  6  inches  long  and  23  feet  6  inches  wide 
over  all ;  each  of  the  sides  of  the  hull  is  made  of  four  pieces 
of  yellow  pine,  the  two  lower  8  X  14  inches,  the  third  7  X  14 
inches,  the  top  piece  6  X  14  inches,  all  securely  tied  by 
through  bolts. 

The  bow  planking  is  oak  5  inches  thick ;  the  bottom  and 
end  plank,  yellow  pine  3  inches  thick.  The  bow  is  further 
strengthened  by  a  16  X  16-inch  cross  timber  at  top,  and  at 
the  stem  is  an  8  X  12-inch  cross  timber  of  yellow  pine.  Oak 
is  used  on  the  bow  as  being  better  adapted  to  stand  the  con- 
stant wear  of  the  piles  hauled  against  it.  To  prevent  knots 
or  inequalities  on  the  piles  from  interfering  with  their  posi- 
tion under  the  hammer,  the  bow  planking  overhangs  6  inches 
in  its  total  height. 

The  hull  is  especially  designed  to  obtain  longitudinal  stiflf- 
ness  so  that  the  strain  between  the  bow  and  engine  may  be 
properly  distributed.  To  attain  this  end  the  hull  is  strength- 
ened lengthwise  by  four  longitudinal  bulkheads,  or  keelsons 
/",  each  6  inches  thick  and  braced  laterally  by  four  sets  of  X 
braces  g,  made  of  6  X  6-inch  timber.  The  hull  is  further 
braced  in  the  center  by  two  3  X  12-inch  yellow  pine  braces 
//,  and  tie-rods  or  "  log  chains  "  k  of  iron  If  inches  in  diam- 
eter. Wale  pieces  and  fender  plank  /  3  inches  thick  protect 
the  outside  of  the  hull  against  chafing;  the  deck  has  a  crown 
of  about  6  inches  in  its  total  width. 

The  leaders  in,  in  are  made  of  two  pieces  of  12'  X  12'  yel- 
low pine  67  feet  long  from  out  to  out,  with  inside  guides  ;/ 
of  4  X  5-inch  stuff  protected  by  plate  iron  one-fourth  inch 
thick;  five-eighths  inch  bolts  with  countersunk  heads  fas- 
ten the  inner  guides  to  the  main  sticks  and  at  the  same  time 
secure  the  iron  work  to  the  same.     The  bottoms  of  the  leaders 


1012 


RAILROAD   CONSTRUCTION. 


are  connected  with  the  12  X  12-inch  bed  pieces  o  by  two 
timber  knees  not  shown,  and  are  tied  at  the  top  by  the  cap/. 
The  arrangement  of  the  back  braces  q,  r,  and  s  is  clearly 
shown  in  the  elevation.  Their  dimensions  are,  respectively, 
6  X  12,  5  X 10,  and  5  X  12  inches.     They  are  of  yellow  pine 


Fig.  480. 

and  securely  bolted  at  the  top  and  bottom  with  seven-eighths 
inch  bolts. 

The  side  braces  «  and  v  are  of  round  timber  16  inches  in 
diameter  at  butt,  and  each  anchored  to  the  hull  by  two  heavy 
timber  knees.  The  bed  pieces  o  are  fastened  down  to  the 
hull  by  four  bolts  each  one  inch  in  diameter,  the  forward 
bolt  passing  through  the  16  X  16-inch  oak  piece  w  on  the 


RAILROAD   CONSTRUCTION. 


1013 


bow,  and  the  after  bolts  passing  through  a  cross  timber  x^ 
6  X  14  inches.  The  bottoms  of  the  back  braces  are  secured 
to  the  bed  timbers  by  1-inch  strap  bolt  in  each  timber,  the 
strap  portion  of  the  bolt  being  2  inches  x  i  inch  in  section. 
A  seven-eighths  inch  through  bolt  ties  the  three  braces 
together.  The  iron  stayrods  running  from  heads  of  lead- 
ers to  the  after  part  of  hull  are  two  in  number,  and  each  one 
inch  in  diameter. 

The  hoisting  sheaves  on  top  are  two  in  number,  placed 
side  by  side.  They  are  12  inches  in  working  diameter, 
15^  inches  from  out  to  out,  and  3^  inches  wide,  and  the  pin 
passing  through  them  is  2|- inches  in  diameter  at  the  sheaves 
and  2  inches  in  diameter  in  the  boxes.  These  dimensions 
are  none  too  great  to  stand  the  severe  work  frequently  put 
upon  the  sheaves  in  hoisting  heavy  weights  and  tearing  out 
timber.  The  fall  or  hammer  rope  is  2  inches  in  diameter, 
and  the  "runner  "  used  in  hoisting  up  piles  is  If  inches  in 
diameter. 

The  hoisting  engine  is  double-drummed  and  of  nominally 
25  H.  P.  The  detail  of  the  hammer,  shown  at  E,  gives  a 
clear  idea  of  its  general  design.     The  weight  is  3,300  pounds. 

1586.  Sheet  Piles.  —  In  building  cofferdams  for 
foundations  and  often  in  protection  work,  piles  are  driven 
in  close  contact  to  prevent  leakage.     Such  piles  are  called 


LXlXiOj 


I«g^g3 


Fig.  481. 


Fig.  482. 


sheet  piles.  Sheet  piles  are  always  of  sawed  timber. 
Where  the  water  is  shallow  and  without  a  current,  2-in':h 
planks  will  be  sufficient.     As  the  depth  of  water  and  pressure 


1014 


RAILROAD   CONSTRUCTION. 


increase,  the  dimensions  of  sheet  piles  increase.  Usually 
they  are  thinner  than  they  are  wide,  but  frequently  they 
are  of  square  timber  and  as  large  as  bearing  piles,  and  are 
then  called  close  piles. 

.  To  make  sheet  piles  drive  close  together  at  foot,  the  points 
are  sharpened  as  shown  at/* in  Fig.  481.  Any  lateral  move- 
ment is  prevented  by  the  wales  o,  o. 

To  keep  the  edges  at  top  close  to  those  already  driven,  a 
dog  iron,  such  as  shown  at  a  in  Fig.  482,  is  often  used. 

A  cut  of  a   standard   sheet   pile  driver  is  given  in  Fig. 
483.     A  general  plan  of  cofferdam  illustrating  the  use  of 


Fig.  483. 

sheet  piling  was  given  in  Fig.  465,  Art.  1554.  The  frame 
is  light,  and  readily  shifted  by  hand.  The  hammer  A  is 
oak.  It  is  raised  by  the  rope  B^  which  works  in  the  single 
pulley  C.  The  hammer  is  usually  worked  by  hand,  three  or 
four  laborers  generally  being  sufficient. 

1587.  Cost  of  Pile  Driving.— The  following  figures 
on  the  cost  of  pile  driving  are  taken  from  reports  published 
in  the  Engineering  Nezvs  : 


RAILROAD   CONSTRUCTION. 


1015 


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1016  RAILROAD   CONSTRUCTION. 

Cost  of  Piles. — At  Chicago,  and  points  on  the  Mississippi 
river  at  and  above  St.  Louis,  pine  piles  cost  from  10  to 
15  cents  per  lineal  foot,  according  to  length  and  location. 
Soft  wood  piles,  including  cottonwood,  rock  elm,  etc.,  can 
be  had  at  any  point  for  from  8  to  10  cents  per  lineal  foot. 
Oak  piles  20  to  30  feet  long  cost  from  10  to  12  cents  per  foot ; 
30  to  40  feet  long,  from  12  to  14  cents;  40  to  60  feet  long, 
from  "20  to  30  cents  per  foot. 

The  tables  of  cost  which  follow  are  for  various  classes  of 
work. 

Railroad  Construction. — The  accompanying  table  of  cost  is 
exclusive  of  first  cost  of  piles  and  of  the  expense  of  hauling. 
Piles  used  in  construction  of  the  Chicago  branch  of  the 
Atchison,  Topeka  and  Santa  Fe  Railroad.  Piles  were 
driven  ahead  of  the  track  by  a  horsepower  drop  hammer 
weighing  2,200  pounds.  Average  depth  driven,  13  feet. 
Table  includes  cost  of  driving  piles  for  foundations  of  Howe 
truss  bridge,  and  for  false  work  used  in  the  erection  of 
same.  The  contractor  received  the  same  price  for  all 
classes  of  work.  .  The  work  was  varied,  the  piles  being 
driven  into  all  kinds  of  soil.  Wages  for  labor  were  high, 
and  as  follows:  Foreman,  $4  per  day;  six  laborers,  at  12; 
two  teams  at  $3.50;  total  cost  for  labor,  123  per  day.  Work 
in  progress  in  the  year  1887. 

Number  of  piles  included  in  report 4,409 

Number  of  lineal  feet  included  in  report.  .  .  .109,578 

Average  length  of  piles  in  feet 24.8 

Number  of  days  employed  in  driving 491 

Number  of  lineal  feet  driven  per  day 223.2 

Cost  of  driving,  per  pile $2.53 

Cost  of  driving,  per  foot 10.2  cents 

Bridge  construction,  Northern  Pacific  Railroad  bridge 
over  Red  River,  at  Grand  Forks,  Dakota,  constructed  in 
1887.  Soil,  sand  and  clay.  The  penetration  under  a  2,250 
pound  hammer,  falling  30  feet,  was  2  to  4  inches.  The 
foreman  received  $5  per  day,  stationary  engineer  $3.50  per 
day,  and  laborers  $2  per  day. 


RAILROAD   CONSTkT:fCTlON. 


1011 


In  the  construction  of  a  railroad  in  Southern  Wisconsin 
during  1885-  87,  the  contract  price — the  lowest  competitive 
bid — for  piles  in  place  under  the  piers  of  several  large 
bridges,  averaged  as  in  the  following  table.  The  piles  were 
driven  in  a  strong  current  and  sawed  off  under  water;  hence, 
the  comparatively  great  expense : 

CONTRACT  PRICE  FOR  FOUNDATION  PILES. 


Kind  of 
Driving. 

Contract  Price  per  Lineal  Foot. 

Material  of  Pile. 

For  Part 

Remaining  in 

Structure. 

For  Pile  Heads 
Sawed  Off. 

Rock  Elm 
Pine 
Oak 
Oak 

Ordinary 

Ordinary 

Ordinary 

Hard 

40  cents. 
40  cents. 
48  cents. 
50  cents. 

15  cents. 
20  cents. 
25  cents. 
30  cents. 

ESTIMATES. 

1588.  Calculating  Cross-Sections. — Cross-sections 
are  the  basis  of  most  calculations  employed  in  determining 
the  amount  of  material  handled  in  grading  the  roadway. 
A  full  description  of  the  method  of  taking  and  recording 
cross-sections  was  given  in  Arts.  1457  and  1458.  The 
cross-section  notes  are  copied  into  a  Qtia^ttity  Book,  and  the 
total  end  areas  of  the  cross-sections,  together  with  the 
partial  areas  representing  the  classification  of  the  material 
as  determined  by  the  excavations,  are  placed  in  regular 
order.  On  the  same  line,  under  their  proper  headings,  are 
placed  the  quantities  of  the  different  materials  excavated 
between  .the  two  points  of  the  line  where  the  cross-sections 
are  taken. 

The  common  practice  in  calculating  quantities  from 
cross-sections  is  to  multiply  the  mean  or  average  area  in 


1018  RAILROAD   CONSTRUCTION. 

square  feet  of  two  consecutive  sections  by  the  distance  in 
feet  between  them. 

Thus,  let  A  represent  the  area  in  square  feet  of  one  sec- 
tion; B,  the  area  in  square  feet  of  the  next  section;  C,  the 
number  of  feet  between  the  sections,  and  Z>,  the  total  num- 
ber of  cubic  feet  in  the  prismoid  lying  between  these  sections. 
Then,  by  common  practice, 

/)  =  ^±^XC.  (IIO.) 

Example. — Two  consecutive  cross-sections  are  50  feet  apart.  The 
area  of  one  is  150.4  square  feet,  and  of  the  other  is  191.3  square  feet. 
What  is  the  volume  of  the  included  prism  ? 

Solution. — Substituting  the  given  quantities  in  the  above  formula. 

we  have  volume  =  ^^^-^  +  ^^^-^  X  50  =  8.542.5  cu.  ft.  =  316.39  cu.   yd. 

Ans. 

1589.  The  Prismoidal  Formula. — A  more  accurate 
result  is  obtained  by  the  use  of  the  prismoidal  formula.  In 
applying  the  prismoidal  formula  to  the  calculation  of  cubic 
contents,  it  is  requisite  to  know  the  middle  cross-section 
between  each  two  that  are  measured  on  the  ground.  The 
dimensions  of  this  middle  section  are  the  mean  of  the 
dimensions  of  the  end  sections. 

Calling  one  of  the  given  sections  A,  the  other  B,  the 
average  or  mean  section  M,  the  distance  between  the  sec- 
tions L,  and  the  required  contents  S,  we  have,  by  the 
prismoidal  formula, 

S  =  ^{A  +  4.M+B).  (111.) 

In  calculating  the  cubical  contents  of  the  prismoid  in- 
cluded between  the  following  sections,  both  methods  of  cal- 
culation will  be  used  and  the  two  results  compared.  The 
sections  are  represented  by  Figs.  484  and  485,  and  are 
denoted  by  the  letters  y^i  and  B.  The  perpendicular  distance 
between  them  is  50  feet.  The  section  given  in  Fig.  484  is 
composed  of  the  four  triangles  a,  hy  f,  and  d.     The  triangles 


RAILROAD   CONSTRUCTION. 


1019 


a  and  b  have  equal  bases  of  9  feet,  the  half  width  of  the 
roadway;  hence,  if  we  take  half  the  sum  of  their  altitudes 
and  multiply  it  by  the  common  base  we  shall  have  the  sum 
of  the  areas  of  the  triangles  a  and  b. 

The  triangles  c  and  d  have  a  common  base  "8  feet,  the 
center  cut  of  the  section,  and  if  we  take  the  half  sum  of  the 
side  distances  and  multiply  it  by  8  feet,  we  shall   obtain 


Fig.  484. 


Fig.  485. 


the  areas  of  the  triangles  c  and  d.     Taking  the  dimensions 
of  section  A  given  in  Fig.  484,  we  have 

Area  of  triangles  a  -{-  b  =  — '—^ —  X  9  =    80. 1  sq.  ft. 

21  8  -I-  14 
Area  of  triangles  c  -^  d  =  — '-^ —  X  8  =  143.2  sq.  ft. 

Total  area  of  section  A  —  223.3  sq.  ft. 

Taking  the  dimensions  of  the  section  B  given  in  Fig.  485, 
we  have 


1020 


RAILROAD   CONSTRUCTION. 


9  7  -j_  2  2 
Area  of  triangles  a'-^  d'=  —- — f- ^ —  X  9  =    53.55  sq.  ft. 

Area  of  triangles  c'-\-  d' —  — '■ — ^ — —  X  5  =    74.75  sq.  ft. 


Total  area  of  section  B  =  128.3    sq.  ft. 

AT                    f       ^-         ^       A  n      223.3  +  128.3       _^  ^ 
Mean  area  or  sections  A  and  z>  = ir =  175.8 

^^  sq.  ft. 

Contents  of  the  included  prismoid  =  175.8  x  50  =  8,790 
cu.  ft.  =325.6  cu.  yd. 

In  applying  the  prismoidal  formula  we  calculate  the  area 
of  a  section  midway  between  the  given  sections,  and  for  its 
dimensions  we  take  the  mean  of  the  dimensions  of  the  given 
sections.     These  dimensions  will  be  as  follows: 


Center  cut, 


8  +  5 


=    6.5    ft. 


R.ight  side  distance,    — ^^^^r — —  =  12.6    ft. 

Left  side  distance,     — '- — ^ — '—  =  20.25  ft. 

With  these  dimensions,  construct  the  section  M  shown  in 
Fig.  486. 


Fig.  486. 


The  area  of  section  M  is  computed  by  the  same  method 
as  that  used  with  sections  A  and  B  in  Figs.  484  and  485, 
and  is  as  follows: 


RAILROAD   CONSTRUCTION.*  1021 

Area  of  triangles  a'  +  b"  =  "*"'— -X  9     =66.6  sq.  ft. 

on  9_1_  19  R 

Area  of  triangles  c'  -^d"  =         I^  x  6.5  =  106.6  sq.  ft. 

Total  area  of  section  M=  173. 2  sq.  ft. 

Denoting  the  distance  between  the  sections  by  Z,  and  the 
cubical  contents  of  the  prismoid  by  S,  we  have,  by  applying 
the  prismoidal  formula  111, 

S=^{A+4.M+B). 

Substituting  known  values  in  the  formula,  we  have  S  = 
y  (223.3  +  4  X  173.2  +  128.3)  =  8,703  cu.  ft.  =  322.3  cu.  yd. 
Ans. 

Comparing  the  results,  we  have 

By  averaging  end  areas,  contents  =  325.6  cu.  yd. 
By    prismoidal  formula,  contents  =  322.3  cu.  yd. 
A  difference  of  about  1  per  cent. 

Fig.  487  represents  a  mixed  section  of  which  the  part 
a  b  c  \^  solid  rock,  the  partcde/is  loose  rock  and  the 
part  d  e  g  h  is  earth.  The  slope  a  c  in  solid  rock  is  ^  hori- 
zontal to  1  vertical.  In  a  section  where  the  excavated 
material  is  classified,  the  foregoing  methods  of  computing 
areas  can  not  be  employed  except  to  check  the  aggregate 
area,  and  when  the  slopes  vary  with  the  different  materials 
other  methods  must  be  entirely  used. 

Where  there  is  no  indication  of  rock,  the  slope  stakes  are 
set  to  the  usual  slope  of  1  horizontal  to  1  vertical.  If  rock 
is  encountered  before  the  rock  excavation  is  commenced, 
the  slope  is  contracted  to  ^  horizontal  to  1  vertical. 

It  has  been  customary  to  plat  irregular  sections  on  cross 
section  paper.     The  original  or  surface  cross-sections  are 
first  platted,  and  when  the  top  material  (usually  earth)  has 
been  removed,  a  cross-section  of  the  remaining  material  is 
taken  and  platted  on  the  original  sheet,  the  lines   being 


1022 


RAILROAD   CONSTRUCTION. 


drawn  in  colored  ink.  If  there  is  still  another  classification 
of  material,  as  shown  in  Fig.  487,  a  final  cross-section  is 
taken  and  platted  in  lines  of  a  separate  color. 

The  different  colored  lines  at  once  indicate  the  outlines  of 
the  various  materials  and  assist  in  checking  the  calculations 
of  the  partial  areas.  The  original  cross-sections  and  the  fin- 
ished section  should  be  in  black,  the  others  in  distinct,  sep- 
arate colors. 

The  partial  areas  are  easiest  calculated  by  dividing  them 
into  triangles  and  carefully  scaling  all  dimensions  not 
given. 

hyCut  13' 


Fig.  487. 


In  Fig.  487  we  have,  remembering  that  the  slopes  of  /^ 
and  c  Ji  are  1  to  1 : 


Total. 

9x3 

=  18.0   sq.ft. 

18.0  sq.ft. 

9X1 

=    9.0   sq.ft. 

11X2.1 

=  C3.1    sq.ft. 

10x2.1 

=  21.0   sq.ft. 

Area  of  triangle  a  b  c  oi  solid  rock  = 
Area  of  triangle  b  e /oi  loose  rock  = 
Area  of  triangle  b  e  k  oi  loose  rock  = 
Area  of  triangle  c  b  koi  loose  rock  = 
Area  of  triangle  c  d  /&  of  loose  rock  =13.2x1. lo=  15.2   sq.  ft.    68.3sq.  ft. 
Area  of  triangle  rt'*?  ^'- of  earth          =27.2x1.65=  44.88  sq.  ft. 
Area  of  triangle  ^/^^ // of  earth          =34.    x2.2=74.8   sq.  ft.  119.7sq.  ft. 
Total  area  of  section 206.0sq.  ft. 


1590.  Quantity  Books. — Quantity  books  spoken  of 
in  Art.  1588  are  of  various  forms.  The  following  is  rec- 
ommended. It  contains  station  and  cross-section  notes  of 
Fig.  487,  together  with  the  end  areas: 


RAILROAD   CONSTRUCTION. 


1023 


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1024  RAILROAD    CONSTRUCTION. 

This  form  of  notes  includes  both  left  and  right-hand  pages 
of  the  book,  and  the  classification  of  material  meets  the  re- 
quirements of  most  railroad  work.  When  the  material  in- 
cluded between  two  consecutive  cross-sections  is  of  the  same 
character,  the  prismoidal  formula  should  be  used  in  calcu- 
lating the  cubical  contents  of  the.  included  prismoid,  but 
when  the  sections  are  classified,  as  in  Fig.  487,  the  mean 
area  of  each  material  shown  in  both  sections  should  be  taken 
and  multiplied  by  the  distance  between  the  sections.  When 
one  kind  of  material,  such  as  rock,  shows  in  one  section  and 
not  in  the  next  following,  the  point  where  that  particular 
material  ends  should  be  determined  and  the  distance  from  it 
to  the  section  containing  rock  should  be  measured.  This 
mass  of  rock  will  be  considered  either  as  a  pyramid  or  a 
wedge,  according  to  its  form.  When  of  wedge  form,  its  vol- 
ume is  the  product  of  its  base  by  one-half  its  altitude  or 
length,  and  when  of  pyramid  form  its  volume  is  the  product 
of  its  base  by  one-third  its  altitude  or  length. 

The  partial  and  total  areas  of  each  section  are  placed  on 
the  same  line  under  their  proper  headings.  As  the  number 
of  the  station  at  which  each  cross-section  is  taken  is  given 
in  the  station  column,  the  distance  between  any  two  sec- 
tions is  readily  found  by  subtraction.  The  quantities  are 
carried  out  on  the  same  line  as  the  end  areas  and  placed 
under  their  proper  headings.  Thus,  in  calculating  the  ma- 
terial between  Sta.  50  and  Sta.  50  -f-  50,  place  the  quanti- 
ties on  the  Sta.  50  +  50  line,  which  is  next  below  Station  50. 
When  a  page  of  the  quantity  book  is  filled,  add  the  several 
columns  of  quantities  which  are  given  in  cubic  feet,  and  re- 
duce them  to  cubic  yards  by  dividing  by  27.  At  the  end  of 
each  mile  section  a  blank  page  should  be  left  in  the  quantity 
book.  A  summary  of  the  total  yardage  of  each  kind  of  ma- 
terial handled  in  the  grading  of  the  section  is  then  made  out 
and  placed  on  this  blank  page,  together  with  the  contract 
price  and  value  of  the  work.  Wherever  a  trestle  or  cul- 
vert occurs,  a  space  should  be  left  in  the  quantity  book  at 
the  proper  station,  large  enough  to  contain  a  sketch  and 
estimate  of  the  materials  for  the  same.     Spaces  should  alsq 


RAILROAD   CONSTRUCTION.  1025 

be  left  for  borrow  pits  and  any  special  excavation.  All 
these  partial  estimates  will  appear  in  the  summary  in  proper 
order.     The  following  will  serve  for  a  guide: 

SUMMARY    OF    QUANTITIES. 


SECTION    lO. 

Excavation. 

Earth 10,000  cubic  yards  @  20c $2,000.00 

Loose  rock 1,500  cubic  yards®  40c 600.00 

Solid  rock    850  cubic  yards  @  80c 680.00 

Borrow   2,000  cubic  yards  @  20c 400.00 

Masonry. 

First-class  ....  190  cubic  yards  @  110.00 $1,900.00 

Second-class  ...  220  cubic  yards  @      6.00 1,320.00 

Rubble 270  cubic  yards®      4.00 1,080.00 

Rip-rap 300  cubic  yards  ®      60c 180.00 

Paving 120      sq.  yd.      @      90c 108.00 

Piling. 

4,000  lineal  feet  @  30c .^ $1,200.00 

Trestle    Timber. 

100,000  feet  board  measure,  in  work  @$30 $3,000.00 

Iron. 

3,000  pounds  @  4c $120.00 

Total  cost  of  grading,  masonry,  and  trestling  on 

Section  10 $12,588.00 

1591.  Monttily  Estimates. — On  or  about  the  last 
day  of  every  month  during  the  progress  of  construction, 
measurements  are  taken  to  determine  the  total  amount  of 
work  done  and  materials  furnished  up  to  that  date.  It  is 
frequently  necessary  to  take  measurements  for  both  monthly 
and  final  estimates  at  other  times  than  the  closing  days  of 
the  month.  This  is  especially  the  case  in  foundation  work 
where  the  masonry  is  started  as  soon  as  the  excavations  are 
completed.     When    the  roadway  has  been  completed,  the 


1026  RAILROAD   CONSTRUCTION. 

monthly  and  final  estimate  will  be  the  same.  The  quanti- 
ties  are  taken  directly  from  the  quantity  book,  where  end 
areas  of  sections  and  volumes  are  carefully  calculated  and 
carried  out  in  regular  columns. 

An  approximate  estimate  is  made  of  all  work  in  progress, 
care  being  taken  to  make  it  as  exact  as  the  nature  of  the 
work  will  allow. 

A  special  field  book  is  used  for  monthly  estimates,  in 
which  a  description  is  given  of  the  particular  work  or  struc- 
ture measured,  together  with  the  date  of  measurement.  The 
notes  consist  principally  of  the  cross-sections  of  incompleted 
roadway.  Wherever  the  roadway  is  completed  to  grade, 
the  word  "  completed  "  is  commonly  written  opposite  the 
station  and  the  quantities  computed  from  the  original  cross- 
sections.  Notes  of  foundation  pits  are  made  doubly  clear 
by  a  sketch  of  the  excavation  with  dimensions  marked  on 
the  outlines.  All  special  work,  concerning  which  a  misun- 
derstanding may  possibly  arise,  must  be  particularly 
described. 

Materials,  such  as  lumber,  stone,  etc.,  furnished  by  the 
contractor  and  not  put  into  any  structure  at  the  time  the 
estimate  is  taken,  should  be  measured  and  the  amounts 
placed  under  the  head  of  temporary  allowances^  the  price 
allowed  being  somewhat  less  than  the  actual  value  of  the 
material  as  delivered. 

Blank  forms  are  used  by  the  resident  engineer  in  reporting 
monthly  estimates.  In  these  forms  a  column  is  provided  for 
each  of  the  different  classes  of  material  and  work  contained 
in  the  contract.  The  stations  are  numbered  in  the  first  col- 
umn in  regular  order,  and  opposite  each  station  in  the 
proper  column  the  amount  of  excavation,  masonry  etc.,  is 
written. 

An  estimate  is  made  for  each  particular  mile  section  into 
which  the  line  of  railroad  is  divided  for  letting. 

The  resident  engineer  should  keep,  in  a  separate  book,  a 
record  of  each  monthly  estimate. 

The  monthly  estimates  are  forwarded  to  the  division  en- 
gineer, who  reviews  them,  copying  the  footings  of  the  several 


RAILROAD   CONSTRUCTION.  1027 

columns  into  a  separate  book  in  which  the  sections  of  his  di- 
vision are  placed  in  regular  order.  The  prices  are  affixed  to 
the  quantities  and  the  total  amounts  carried  out.  From  the 
totals,  the  amounts  of  previous  estimates  are  deducted,  and 
the  remainder  is  the  amount  due  the  contractor  for  the 
month.  From  this  amount  a  certain  percentage  (usually  15 
per  cent.)  is  deducted  to  be  reserved  by  the  company  until 
the  completion  of  the  contract. 

A  summary  of  the  monthly  estimate  is  then  forwarded  by 
the  division  engineer  to  the  chief  engineer  for  auditing  and 
approval. 

1592.  The  Final  Estimate. — The  final  estimate  is 
a  complete  statement  in  detail  of  the  amount  of  work  done 
and  the  materials  furnished  in  the  construction  of  the  road, 
and  is  the  basis  of  final  settlement  between  the  company  and 
the  contractor.  It  should  be  commenced  as  soon  as  con- 
struction is  under  way  and  continued  as  fast  as  the  necessary 
data  may  be  collected. 

Full  notes  must  be  kept  of  each  particular  structure  and 
complete  measurements  taken  while  the  work  is  under  way 
and  the  circumstances  fresh  in  mind.  This  is  particularly 
important  in  the  case  of  bridge  and  culvert  foundations  and 
other  structures,  either  under  water  or  covered  with  earth  at 
the  completion  of  the  work.  These  sketches  and  notes  will 
be  recorded  at  their  proper  station  in  the  quantity  book 
described  in  Art.  1590.  When  the  work  is  completed,  a 
final  summary  is  made  containing  the  aggregate  quantities 
of  the  entire  line. 

Full  notes  are  kept  of  all  classified  materials  and  of  all 
material  affected  by  length  of  haul  (providing  a  haul  clause 
occurs  in  the  contract)  and  arranged  in  the  order  in  which 
the  work  occurs  on  the  line. 

The  calculations  for  final  estimate  limit  the  monthly 
estimates  and  guide  the  engineer  in  making  approximate 
estimates  of  either  work  or  material. 


TRACK   WORK. 


TRACK  LAYING. 

1593.  There  is  no  department  of  modern  railroad 
engineering  which  is  receiving  so  much  attention  as  the 
care  and  maintenance  of  the  track.  In  the  great  strife  for 
business,  freight  and  passenger  rates  have  been  reduced  to 
a  minimum,  and  to  meet  these  conditions  speed  and  train 
loads  have  been  nearly  doubled.  These  conditions  demand 
a  good  track. 

A  track  to  be  good  must  be  laid  on  sound  ties,  well 
ballasted  and  surfaced,  full  spiked  and  bolted,  and  in  perfect 
line  and  surface. 

1594.  New  Road. — In  America  practically  all  newly 
constructed  railroad  is  built  of  new  material  throughout, 
though  the  cross-ties  are  often  cheap  and  the  rails  light. 


CROSS-TIES. 
1595.     Cross-ties  are  of  wood.     Their  size  and  variety 
of  timber  will  depend  upon  the  locality  and  financial  ability 
of  the  railroad  company.     The  best  ties  are  of  white  oak. 

The  following  list  gives  in  a  descending  scale  the  com- 
parative values  of  woods  for  cross-ties : 

Hard  Wood.  Soft  Wood. 

White  Oak.  Red  Cedar. 

Rock  Oak.  Black  Cypress. 

Burr  Oak.  White  Cedar. 

Chestnut.  White  Cypress. 

Southern  Pine.  Tamarack. 

Walnut.  Butternut. 

Cherry.  White  Pine. 

Red  Beech.  Hemlock. 

Red  Oak.  Spruce. 


1030 


TRACK  WORK. 


It  is  generally  accepted  that  hewn  ties  are  superior  to 
sawed  ties.  The  surface  of  a  well-hewn  tie  is  a  series  of 
comparatively  smooth  surfaces.  The  effect  of  the  ax  is  to 
close  the  pores  as  the  chip  is  removed,  which  tends  to  exclude 
the  moisture.  The  effect  of  the  saw  is  exactly  the  reverse 
of  the  ax.  While  given,  an  average  smoother  surface,  it 
tears  the  fiber  of  the  wood,  leaving  the  pores  open.  These 
minute  broken  fibers  which  cover  the  entire  surface  of  the 
tie  act  like  sponges  in  attracting  and  retaining  moisture, 
and  eventually  hasten  decay. 

1 596.  Importance  of  Seasoning. — Too  little  atten- 
tion is  paid  to  the  seasoning  of  cross-ties  before  they  are 
laid  in  the  track.  This  is  especially  true  on  newly  con- 
structed lines  where  scarcity  of  capital  and  the  necessity  for 
keeping  down  expenses  compel  the  use  of  the  cheapest 
material  and  methods.  Cross-ties  thoroughly  seasoned  will 
last  fully  one-quarter  longer  than  those  used  while  green, 
and  they  are  better  in  every  way.  Well-seasoned  wood  will 
hold  the  spikes  better  and  resist  the  shearing  tendency  of 

the  rails  due  to  passing 
loads  better  than  green 
ties.  The  most  favorable 
months  in  Northern  lati- 
tudes for  cutting  ties  are 
August,  December,  Janu- 
ary, and  February.  Dur- 
FiG.  488.  ing  these  months  there  is 

comparatively  no  movement  in  the  sap  of  the  trees.  The 
ties  should  be  hewn  to  uniform  thickness  and  piled  in  square* 
piles  about  4^  feet  in  height,  as  shown  in  Fig.  488,  so  as  to 
admit  of  the  free  circulation  of  the  air  and  to  hasten  the 
seasoning  process. 

1597.  Specifications  for  and  Inspection  of 
Cross-Ties. — Specifications  should  include  dimensions,  and 
kind  and  quality  of  timber.  Ties  for  standard  gauge  tracks 
should  be  from  8  to  9  feet  in  length,  from  6  to  8  inches  in 
thickness,  and  show  not  less  than  6  inches  of  face.     The 


TRACK  WORK.  1031 

standard  tie  is  8  feet  6  inches  in  length,  7  inches  in  thick- 
ness, and  shows  at  least  7  inches  of  face.  In  the  Northern, 
Middle,  and  Western  States,  log  ties,  i.  e.,  ties  cut  from 
entire  trees  and  showing  two  rounded  sides,  are  principally 
used.  In  the  Southern,  Atlantic,  and  Gulf  States,  yellow 
pine  ties  are  in  almost  universal  use.  They  are  square  hewn 
and  made  of  heart  timber,  not  more  than  1  inch  of  sap  being 
allowed  on  the  corners.  In  Southern  latitudes,  where  the 
process  of  decay  goes  on  throughout  the  year,  sap  timber  is 
almost  worthless.  The  sap  timber  soon  softens,  the  spikes 
loosen  and  the  rails  cut  into  the  wood,  leaving  the  track  in 
a  dangerous  state.  In  those  portions  of  the  South  where 
oak  is  abundant,  oak  ties  are  much  used.  They  are  generally 
square  hewn.  This  is  a  mistake,  especially  if  the  ties  are 
cut  from  young  thrifty  trees  (and  no  other  timber  should  be 
used),  since  a  considerable  portion  of  the  weight  of  the  tie 
is  sacrificed  in  squaring.  This  lost  weight  is  all  needed  to 
give  stability  to  the  track.  The  ties  should  be  cut  off  square 
and  to  uniform  lengths,  and  be  of  a  uniform  thickness 
throughout  their  entire  lengths.  Before  being  inspected, 
they  should  be  delivered  along  the  right-of-way  of  the  rail- 
road and  piled  in  regular  piles,  each  tie  showing  both  ends. 
Ties  are  commonly  graded  as  firsts  and  seconds.  The  in- 
spector carries  a  brush  and  pot  of  paint,  marking  each  class 
of  ties  with  a  distinctive  mark.  Firsts  are  usually  marked 
by  a  full  circle,  and  seconds  by  a  cross. 


PREPARATION  OF  A  ROADBED. 
1598.  It  is  a  rare  thing  to  find  a  new  roadbed  in  proper 
condition  for  track  laying.  Often  it  is  in  poor  surface,  being 
left  by  the  contractors  in  a  rough,  uneven  state.  If  the  track 
is  being  laid  in  heavy,  wet  weather  and  .the  ties  are  being 
distributed  by  teams,  the  wheels  are  sure  to  cut  deeply  into 
the  roadbed,  and  unless  some  precaution  is  taken  to  bring 
the  tops  of  the  ties  to  a  uniform  surface,  there  is  great 
danger  of  the  rails  being  bent  by  the  passage  of  the 
construction  train. 


1033  TRACK  WORK. 

1599.  Track  Centers. — Center  stakes  marking  the 
alinement  are  driven  at  intervals  of  100  ft.  on  tangents  and 
50  ft.  on  curves,  where  the  degree  of  curve  does  not  exceed 
12°.  On  curves  exceeding  12°,  stakes  should  be  driven  at 
intervals  of  25  ft.  A  tack  is  driven  in  each  stake,  marking 
the  center  of  the  track.  Grade  stakes  for  surfacing  ties 
should  be  placed  at  intervals  of  10  ft.  A  straight  edge 
placed  upon  these  stakes  marks  the  grade  for  the  inter- 
vening ties.  The  ties  are  bedded  with  earth  taken  from 
the  roadbed  and  tamped  with  the  shovel. 

The  placing  of  grade  stakes  so  close  together  is  contrary 
to  common  practice,  but  the  increased  labor  for  the  engineer 
is  more  than  compensated  for  by  the  saving  of  the  time  or- 
dinarily consumed  in  sighting  in  ties  where  grade  stakes  are 
set  at  intervals  of  50  or  100  ft.  The  surface  is  sure  to  be 
better  where  the  straight  edge  is  brought  into  use,  and  the 
danger  of  kinking  rails  or  bending  them  out  of  surface  is 
obviated. 

1600.  Track  -  Laying  Machines. — Track  -  laying 
machines  have  been  used  to  some  extent.  The  ties,  as  well 
as  rails  and  fastenings,  are  carried  on  cars.  With  some 
machines  they  are  conveyed  to  the  front  on  rollers;  in 
others,  on  an  endless  belt  which  runs  along  the  sides  of  the 
cars.  The  process  of  track  laying  is  as  follows:  Two  rail 
lengths  are  laid,  bolted,  and  partially  spiked,  and  the  ties 
partially  bedded.  The  cars  are  then  run  forwards  and  the 
process  repeated.  The  progress  of  track  laying  with  a  ma- 
chine is  limited  by  the  amount  of  track  which  can  be  full 
bolted,  spiked,  and  made  fit  for  the  running  of  trains,  and 
ranges  from  1  to  1^  miles  per  day,  1  mile  being  a  common 
average.  Economy  in  the  force  of  track  layers  and  the 
saving  of  team  work  are  the  principal  advantages  claimed 
for  track-laying  machines.  In  mountainous  country,  where 
the  roadbed  is  difficult  of  access  to  teams,  the  track-laying 
machine  has  decided  advantages  over  ordinary  methods,  but 
in  open  country  where  the  roadbed  is  readily  accessible, 
both   ties    and   rails   should   be   hauled   by   teams.      With 


TRACK  WORK. 


1033 


material  distributed  a  considerable  distance  in  advance  of 
the  construction  train,  a  much  larger  force  of  men  may  be 
economically  employed.  If  the  track  laying  is  to  be  rushed, 
the  track-laying  machine  must  take  second  place. 

1 60 1 .  Track-Laying  Outfit. — Before  starting  out  to 
lay  new  track  on  a  new  road,  the  boss  track  layer  should 
make  requisition  for  all  the  tools  necessary  for  expeditious 
work.  These  tools  are  loaded  on  a  car  and  shipped  to  the 
point  where  work  is  to  be  commenced.  Everything  should 
be  in  readiness  for  making  a  good  beginning  before  the  men 
are  brought  on  the  ground.  Any  lack  of  proper  tools  is  cer- 
tain to  cause  awkward  and  often  serious  delay,  and  opera- 
tions must  often  be  suspended  until  the  lack  can  be  supplied 
from  headquarters.  The  following  list  of  tools  will  amply 
supply  a  force  of  100  track  layers,  with  a  reserve  for  extra 
men  in  case  they  should  be  needed,  and  will  be  sufficient  to 
take  the  places  of  tools  worn  out  or  broken  until  a  supply 
can  be  brought  to  the  front : 


Hand  cars 1 

Steel  cars 3 

Push  cars 2 

Shovels 150 

Picks 50 

Lining  bars 12 

Claw  bars 12 

Tamping  bars 12 

Nipping  bars 24 

Cold  chisels 24 

Rail  punches 6 

Chopping  axes 6 

Hand  axes 6 

Striking  hammers 42 

Bush  scythes  and  snaths, 

.  each 3 

Hand  saws 6 

Adzes  6 

Track  gauges  12 


Covered  water  barrels. .  .  2 

Track  levers 2 

Chalk  lines 2 

Spirit  levels 6 

Tape  lines. 6 

Nail  hammers 3 

Monkeywrenches 3 

Lanterns,  red 3 

Lanterns,  white   3 

Water  pails 6 

Tin  dippers 6 

Oil  cans 2 

Oilers 3 

Gallons  of  oil 2 

Pick  handles 24 

Nails,  10  penny,  kegs   ...  1 
Nails,   20,  40,   GO  penny, 

kegs,  of  each 1 

Cross-cut  saws 3 


1034 


TRACK  WORK. 


Adz  handles 6 

Ax  handles 6 

Maul  handles 30 

Red- flags 12 

Sledges,  16  lb.  each 2 

Grindstones 1 

Track  wrenches 24 

Iron  tongs,  pairs 3 

Rail  forks 6 

Expansion  shims 200 

Switch  locks  6 

Rail  drills    2 

Torpedoes,  dozens 4 

Track  jacks 4 

Rail  benders 2 


Curving  hooks 2 

Post  hole  diggers 2 

Tie  poles,  30  ft.  long 2 

Tie  lines,  1,000  ft.  long.  .  1 

Sets  double  harness 1 

Sets  single  harness 1 

Sets  double    and   single- 
trees, each 1 

Wagon  1 

Scraper 1 

Horses  or  mules 2 

Tool  boxes 2 

Files 6 

l:J^-inch  rope,  feet 300 


Car  accommodations  for  track  laying  should  be  the 
following : 

One  supply  and  office  car. 
One  kitchen  car. 
Two  dining  cars. 
Three  sleeping  cars. 

Where  track  laying  is  being  done  a  long  distance  from 
the  base  of  supplies,  a  blacksmith  with  forge  and  tools 
should  accompany  the  outfit. 

1 602.  Distributing  Ties.— When  ties  are  distributed 
along  the  foadbed  by  teams,  they  are  strung  out  in  proper 
numbers,  so  that  the  labor  of  carrying  them  to  their  place  in 
the  track  may  be  as  light  as  possible.  The  largest  of  them  are 
reserved  for  joint  ties,  the  joints  being  located  by  measuring 
from  the  ends  of  the  rails  already  in  place  in  the  track.  By 
measuring  with  a  30-foot  pole,  the  joints  of  rails  may  be 
accurately  located,  a  small  stake  driven  marking  each  joint. 
This  practice  admits  of  the  placing  of  ties  several  rail  lengths 
in  advance  of  the  rail,  thus  affording  working  room  for  a 
much  larger  force  than  could  otherwise  be  handled.  A  tie 
line  for  lining  the  ends  of  the  ties  is  spaced  at  the  proper 


TRACK  WORK.  1035 

distance  from  the  center  line  and  stretched  taut,  being 
fastened  at  suitable  intervals  by  well-driven  stakes.  Joints 
should  not  be  located  at  any  considerable  distance  in  ad- 
vance of  the  rails,  as  the  measurements  are  likely  to  vary  a 
little  and  soon  accumulate  an  error.  These  inaccuracies 
are  obviated  by  checking  the  measurements  frequently  from 
the  ends  of  the  rails  already  in  place  in  the  track.  Care 
must  be  taken  to  place  the  ties  at  right  angles  to  the  center 
line.  Ties  laid  askew  prevent  proper  gauging  of  the  track. 
Ties  should  be  assorted  with  reference  to  thickness  in  order 
that  those  of  uniform  thickness  may  come  together  in  the 
track,  thus  greatly  reducing  the  labor  of  bedding. 

1603.  Bedding  Ties. — As  soon  as  the- ties  are  dis- 
tributed and  lined  they  are  bedded  for  the  rails.  The  process 
is  as  follows :  The  straight  edge  is  placed  on  the  grade  stakes 
and  the  faces  of  the  ties  brought  to  a  uniform  surface  by 
first  sinking  those  which  are  above  grade  and  then  raising 
those  remaining  to  grade  by  throwing  dirt  or  ballast  under 
them  and  settling  them  to  the  correct  level.  It  has  been  a 
general  and  most  pernicious  custom  to  spike  the  rails  to  the 
ties  without  bedding.  Most  rails  will  be  found  to  carry 
from  one  to  a  half  dozen  swinging  ties,  some  of  which  are 
sure  to  get  skewed  before  the  ballast  secures  them.  The 
track  is  full  of  undulations  and  as  the  foundation  is  rough 
and  uncertain,  many  of  the  rails  are  kinked  or  surface-bent 
by  the  passing  construction  train.  Where  ties  are  bedded, 
the  spiking  can  be  better  and  more  expeditiously  done,  and 
the  construction  train  can  follow  at  once  with  entire  safety. 

If  the  track  is  to  be  ballasted  with  cinders  or  broken  stone, 
the  ties  must  not  be  bedded,  in  order  that  the  ballast  may 
occupy  all  the  vacant  space  in  the  roadway.  Nevertheless, 
the  dressing  down  of  uneven  places  in  the  roadway  before 
distributing  the  ties  is  time  and  money  well  spent.  The 
ballasting  must  be  kept  well  up  with  the  track  laying  if 
kinking  of  the  rails  is  to  be  avoided. 

1604.  Organization  of  Forces. — The  foreman  in 
charge  of  track-layers  should  thoroughly  organize  his  forces, 


1036 


TRACK  WORK. 


placing  each  man  where  his  work  will  give  the  best  results. 
Spikers  and  iron  men  are  first  choice.  They  should  be  alert, 
sober  men,  and  should  be  paid  higher  wages  than  the  rest, 
as  upon  their  efficiency  depends  the  excellence  and  progress 
of  the  work.  The  prospect  of  promotion  which  is  thereby 
held  out  to  the  others  promotes  the  industry  and  discipline 
of  the  entire  force. 

A  small  surfacing  gang  immediately  follows  the  track- 
layers. Any  scarcity  of  men  at  the  front  can  be  supplied 
from  this  gang,  and  any  extra  men  at  the  front  can  at  any 
time  be  profitably  added  to  the  surfacing  gang. 

1605.  Locating  Joint  Ties. — The  foreman  should 
detail  two  trustworthy  men  to  locate  the  joint  ties.  They 
carry  a  measuring  pole  of  the  standard  rail  length,  usually 
30  feet,  and  locate  the  joints  by  measuring  from  the  ends  of 
the  fixed  rails.  They  also  complete  the  work  of  spacing  the 
intervening  ties,  which  can  not  be  done  until  after  the  joint 
ties  are  placed. 


TRACK    JOINTS. 
1606.     There  are  two  forms  of  rail  joints  in  general  use, 
viz.,  suspended  and  supported.     Both  forms  have  merits 
peculiar  to  themselves,   but  both  are  rarely  found  on  the 

1^ 


Fig.  489.  Pig.  490. 

same  road,  either  one  or  the  other  being  used  exclusively. 
A  cut  of  a  suspended  joint  is  given  in  Fig.  489,  and  of  a 


TRACK  WORK.  1037 

supported  joint  in  Fig.  490.  In  the  suspended  joint  there 
are  two  joint  ties  spaced  about  6  inches  in  the  clear.  The 
joint  is  spaced  midway  between  the  ties,  which  should  be 
carefully  selected,  have  broad  faces,  and  be  of  uniform  thick- 
ness throughout.  In  the  supported  joint  the  tie  is  placed 
directly  under  the  joint.  The  angle  splices  A  and  B,  which 
are  shown  in  section  at  C,  vary  in  length  from  24  to  36  inches. 
Those  24  inches  in  length  have  4  bolts,  and  those  from 
30  inches  upwards  have  6  bolts.  A  joint  to  be  perfect  should 
have  the  same  strength  as  the  rail  itself,  but  such  a  joint 
has  not  yet  been  devised.  A  vast  amount  of  time  and 
money  has  been  expended  upon  the  development  of  rail 
fastenings.  Iron  chairs  and  fish-plates,  once  in  universal  use, 
have  disappeared.  The  angle  splice  shown  in  section  at  C, 
Fig.  489,  is  generally  accepted  as  the  best  rail  fastening  yet 
invented.  The  prerequisite  of  a  good  rail  fastening  is  a 
strong  shoulder  which  will  closely  fit  under  the  head  of  the 
rail,  and  a  broad  base  closely  fitting  the  base  of  the  rail  and 
extending  its  entire  width,  reaching  down  so  as  to  bear  upon 
the  tie.     The  plates  do  not  fit  closely  to  the  web  of  the  rail, 

H 3^-0- —  ->f 

ae 


FIG.  491. 

but  are  curved  as  shown  in  the  section  C.  The  holes  in  the 
plates  as  well  as  those  in  the  rails  are  oblong  so  as  to  admit 
of  the  expansion  and  contraction  of  the  rails  due  to  changes 
of  temperature. 

Bolts  should  be  of  a  size  suited  to  the  weight  of  the  rail, 
though  there  is  small  danger  of  getting  them  too  heavy. 
Track  bolts  are  usually  fitted  with  nut-locks  of  either  metal 
or  fiber.  Trackmen  should  avoid  straining  the  bolts  when 
setting  up  the  nuts.  A  half  turn  of  the  wrench  after  the 
nut  has  come  to  a  bearing  is  sufficient.  Though  there  are 
still  some  railroad  men  who  strongly  adhere  to  the  supported 
joint,   yet   general  experience  has  abundantly  proved    the 


1038 


TRACK  WORK. 


superiority  of  the  suspended  joint.  The  angle  splice  in  gen- 
eral use  on  trunk  lines  is  3  feet  in  length,  carries  6  bolts,  and 
complete  weighs  from  40  to  60  pounds.  The  joint  is  sus- 
pended, and  the  ends  of  the  splices  also  come  midway 
between  ties,  as  in  Fig.  491. 

The  angle  splices  should  be  slotted  and  spikes  driven 
through  them  into  the  tie  to  prevent  the  creeping  of  the 
rails.  In  the  suspended  joint  there  are  two  slots  in  each 
splice,  as  shown  in  Fig.  489,  and  in  the  supported  joint  but 
one. 

Spike  slots  in  the  rails  are  not  admissible,  as  they  prevent 
the  full  expansion  and  contraction  of  the  rails. 


RAILS. 

1607.  Care  in  Unloading  Steel. — Rails  are  often 
bent  in  consequence  of  careless  handling.  There  is  no  ex- 
cuse for  either  foremen  or  workmen  for  this.  The  rails  are 
unfit  for  laying  until  straightened,  but  they  are  often  laid 
in  a  bent  state,  giving  a  bad  surface  and  line.  The  surest 
remedy  is  proper  Jiandling.  The  rails  are  always  loaded 
properly  at  the  rolling  mill,  and  the  kinks  are  put  in  them 
either  in  transfer  or  in  delivering  on  the  grade.  When  rails 
are  to  be  transferred  from  one  car  to  another,  rails  of  suit- 
able length  should  be  used  as  skids  upon  which  the  rails  to 
be  transferred  are  pushed  from  one  car  to  another.  When 
from  scarcity  of  flat  cars,  rails  are  shipped  in  box  cars, 
rollers  are  placed  in  the  end  doors  of  the  box  car,  and  the 
rails  are  rolled  as  they  are  transferred.  The  rails  should 
always  be  placed  in  regular  order,  as  shown  in  Fig.  492. 


hmPs^ 


Fig.  492. 


Fig.  493. 


In  unloading,  there  should  be  enough  men  to  handle  the 
rails  with  ease  and  dispatch.     The  rail  should  be  lifted  clear 


TRACK  WORK.  1039 

of  the  car  floor  and  carried  to  the  edge  of  the  car.  All 
should  be  ready,  and  at  the  word,  the  rail  dropped  clear  of 
the  car  so  that  it  will  fall  in  the  position  shown  in  Fig.  493, 
in  which  position  the  danger  of  kinking  is  entirely  avoided. 
Other  men  should  stand  on  the  ground  removing  each  rail 
as  soon  as  it  drops,  so  that  one  rail  shall  not  fall  on  top  of 
another.  Rails  must  not  be  dropped  from  the  cars  on  rock 
or  loose  stones,  but  on  dirt,  which  will  insure  their  safety. 

None  but  the  best  men  should  be  employed  on  the  steel 
car.  They  should  be  strong  physically,  understand  plain 
English  thoroughly,  and  be  prompt  and  active.  When 
men,  because  of  difference  of  nationality,  fail  to  readily 
understand  each  other,  confusion  is  sure  and  accident 
almost  certain  to  follow.  The  same  gang  of  men  should 
handle  all  the  steel.  If  the  track  laying  is  to  be  rushed,  at 
least  two,  and  better  three,  steel  cars  should  be  provided, 
which  permits  of  one  being  constantly  at  the  front.  As 
soon  as  a  load  of  steel  is  transferred  from  the  flat  car  to  the 
steel  car,  a  team  of  horses  should  be  hitched  to  it  and  the 
car  hauled  to  the  front.  The  steel  men  at  the  front,  having 
unloaded  their  car,  return  with  it  until  they  meet  the  loaded 
car.  They  then  lift  their  empty  car  from  the  rails  to  the 
side  of  the  track,  allowing  the  loaded  car  to  pass.  The 
steel  men  push  the  loaded  car  the  balance  of  the  way  unless 
the  grade  is  heavy  enough  to  require  a  team. 

Steel  cars  should  be  light  and  strong,  and  capable  of 
carrying  a  heavy  load.  The  car  should  be  of  such  weight 
as  to  be  readily  handled  by  the  steel  crew.  The  wheel  base 
should  be  8  inches  in  width,  so  that  the  car  may  pass  safely 
over  rough  and  poorly  gauged  track. 

1608.  Straightening  Rails. — If  from  any  cause, 
rails  should  be  bent,  they  should  be  carefully  straightened 

A 


Fig.  49^. 

before  being  placed  in  the  track.     If  kinked,  i.  e.,  bent  lat- 
erally as  shown  in  Fig.  494,  they  may  be  straightened  by 


1040 


TRACK   WORK. 


nicking  the  flange  of  the  rail  with  a  cold  chisel  on  the  con- 
vex side  of  the  rail  at  the  point  A  where  the  bend  is  the 
sharpest.  Then,  laying  the  rail  on  its  base,  a  few  sharp 
blows  with  a  sledge  on  the  side  of  the  head  of  the  rail  at 
the  point  A  will  remove  the  kink.  Kinks  may  also  be 
removed  by  means  of  a  rail  bender  or  Jim  crow,  shown 
in  Fig.   495.     The   jim  crow  consists  of  two  heavy  hooks 


Fig.  495. 

a  and  d,  which  fit  over  the  head  of  the  rail.  The  curved 
barV,  which  unites  these  hooks,  is  drilled  at  its  crown,  and 
threaded  to  receive  the  screw  d.  The  cross-bar  i-  unites  with 
the  two  hooks  a  and  d,  and  serves  as  a  guide  to  the  screw  c/. 
Force  is  applied  to  the  screw  by  means  of  the  wrench  /y 
having  a  long  handle. 

If  surface-bent,  as  shown  at  A  in  Fig.  496,  they  are  easiest 


Fig.  496. 


Straightened    with    the    jim    crow.      The    straightening    of 
the  rails  befoi;e  laying  will  avail  but  little  unless  the  ties  are 


TRACK  WORK. 


1041 


well  bedded,  and  all  of  the  rails  given  a  good  bearing  when 
the  track  is  laid. 


1609.  Curved  Rails. — Rails  laid  on  curves  should 
always  be  curved  before  being  placed  in  the  track.  When 
laying  track  on  new  road,  it  is  a  much  better  policy  to  curve 
the  rails  in  the  material  yard  before  forwarding  to  the  track- 
layers. The  material  foreman  should  have  a  list  of  the 
curves  in  the  same  order  in  which  they  occur  in  the  track. 
He  should  be  able  to  determine  the  middle  and  quarter 
ordinates  of  a  30-ft.  rail  for  any  degree  of  curve,  and  should 
curve  each  rail  accordingly.  His  list 
of  curves  will  give  the  station  of  the 
P.  C.  and  P.  T.  of  each,  from  which 
he  will  determine  the  length  of  each 
curve  and  the  number  and  length  of 
rails  required  for  each.  These  rails 
should  be  marked  with  the  number  of 
the  degree  of  the  curve  for  which  they 
are  intended,  and  the  rails  for  each 
curve  should  be  kept  separate  from  the 
other  rails  by  pieces  of  board,  so  as  to 
prevent  any  confusion  when  they  ar- 
rive at  the  front.  One  29|-foot  rail  is 
laid  for  each  6°  of  angle  in  the  curve; 
hence,  for  a  curve  with  a  central  angle 
of  30°,  the  number  of  29|-ft.   rails  re- 


•     J  •    30       . 
quired  is  —  =  o. 
6 


In  laying  the  track, 


the  short  rails  should  be  equally  dis- 
tributed throughout  the  curve.  The 
rails  are  curved  either  with  a  rail  ben- 
der, shown  in  Fig.  495,  or  by  the  aid 
of  a  track  lever  and  curving  hook, 
shown  in  Fig.  497. 

The   latter  process  is  as  follows :  A  fig,  4»7. 

tie  A   is  placed  under  each  end  of  the  rail  B  which  is  to 
be  curved.     A  hook  C  is  placed  under  the  main  track  rail 


1042 


TRACK  WORK. 


between  two  ties,  at  about  6  feet  from  the  end  of  the 
rail  to  be  curved.  The  track  lever  D  is  then  let  into 
the  hook  C^  and  the  men  pry  down  upon  the  rail  B, 
giving  it  the  required  curve.  The  quarter  points  should 
always  be  curved  before  the  center,  as  it  often  happens  that 
the  center  curves  with  the  quarter  points,  thus  saving  time. 
The  practice  of  curving  rails  by  dropping  them  across 
two  ties,  or  pounding  them  with  a  sledge  hammer,  can  not 
be  too  severely  condemned.  By  the  former  method,  an 
angle  instead  of  a  curve  is  often  put  in  the  rail,  and  sledging 
is  liable  to  break  a  rail  outright,  or,  at  least,  put  a  flaw 
in  it  which  may  result  in  actual  fracture  when  laid  in  the 
track.  Some  of  the  worst  accidents  on  record  have  been 
caused  by  broken  rails,  weakened  by  hard  usage  while  being 
curved.  The  following  table  contains  a  list  of  curves  and 
tangents  and  the  number  and  lengths  of  rails  required  for 
each.  With  such  a  list,  the  material  foreman  can  forward 
the  rails  curved  and  assorted.  His  facilities  for  curving 
rails  should  be  of  the  best,  and  with  a  skilled  gang  of 
men  he  can  turn  off  much  more  and  better  work  than 
would  be  possible  at  the  front : 

MATERIAL   FOREMAN'S    LIST   OF   RAILS. 


No.  of 

No.  of 

Station. 

Deg. 
Curve. 

Central 
Angle. 

30-Ft. 
Rails  Re- 
quired. 

29i-Ft. 
Rails  Re- 
quired. 

Remarks. 

40  +  90 

End  of  track. 

25  -f  50 

P.  T. 

43°  12' 

29 

7 

20  +  10 

P.  C.  8°  L. 

o 

35 

14  +  80 

P.  T. 

10+  60 

P.  C.  G^  R, 

25°  12' 

24 

4 

1610.     Assorting  Rail  Lengttis. — Rails  of  different 
lengths   should   never  be   laid    promiscuously.     The   short 


TRACK  WORK.  1043 

rails  should  be  piled  by  themselves  in  the  supply  yard  and 
forwarded  to  the  track-layers  in  such  order  and  numbers  as 
they  may  require.  On  curves,  as  the  inner  rail  forms  a 
smaller  circle  than  the  outer  rail,  it  is  sure  to  gain,  and  to 
maintain  the  joints  in  the  same  relative  position,  this  gain 
must  be  compensated  by  the  use  of  short  rails.  A  list  of 
the  curves  and  the  number  of  short  rails  required  for  each 
should  be  given  to  the  supply  foreman,  whose  business  it  is 
to  forward  the  track  material  in  the  order  named  on  the 
list.  This  table  shows  how  the  material  foreman  makes  out 
his  list. 


EXPANSION    AND    CONTRACTION. 

1611.  In  laying  track,  provision  must  be  made  for 
expansion  and  contraction  of  the  rails,  due  to  changes  of 
temperature.  As  the  temperature  rises  the  rail  lengthens, 
and  unless  sufficient  space  is  left  between  the  ends  of  the 
rails  to  allow  for  the  expansion,  the  ends  of  the  rails  abut 
one  against  another  with  such  force  as  to  cause  the  rails  to 
kink  or  buckle,  marring  the  appearance  of  the  track  and 
rendering  it  unsafe  for  trains,  especially  those  running  at 
high  speeds.  If,  on  the  other  hand,  too  much  space  is  left 
between  the  rails,  the  contraction  or  shortening  of  the  rails 
due  to  severe  cold  may  do  equally  great  harm  by  shearing  off 
the  bolts  from  the  splice  bars,  leaving  the  joints  loose  and 
unprotected.  The  coefficient  of  expansion,  i.  e.,  the  amount 
of  the  change  in  the  length  of  an  iron  bar  due  to  an  increase 
or  decrease  of  1°  F.  is  taken  at  .00000686  per  degree  per  unit 
of  length. 

Example. — If  an  iron  rod  measures  30.015  ft.  at  a  temperature  of 
90°,  what  is  its  normal  length,  assuming  60°  as  the  normal  tempera- 
ture ?  The  temperature  of  the  bar  must  be  90'  —  60°  =  30°  above  the 
normal  temperature. 

Solution.— As  the  increase  in  length  is  .00000686  ft.  per  degree  for 
each  foot  in  length  of  the  bar,  the  total  increase  for  1  foot  of  the  bar 
due  to  a  rise  of  30'  in  temperature  is  .00000686  X  30  =  .0002058  ft.,  and 
for  30  ft.  the  increase  in  length  above  the  normal  is  .0002058  X  30  =^ 
,006174  ft ,  or  about  -^^  of  an  inch.     As  the  rail  at  a  temperature  of  90 


1044 


TRACK  WORK. 


measures  30.015  ft.,  of  which  length  .00617  ft,  say,  .006  ft.,  is  due  to 
expansion,  the  normal  length  of  the  rail  is  30.015  —  .006  =  30.009  ft. 

Ans. 

To  provide  against  the  effects  of  expansion,  an  opening 
is  left  between  the  ends  of  the  rails,  and  to  provide  against 
contraction,  the  holes  in  both  rail  and  splice  bar  are  made 
oblong,  allowing  about  ^  inch  for  extreme  movement.  The 
following  /ab/e  of  expansion  is  a  safe  guide  to  track-layers 
for  most  latitudes  in  the  temperate  zones: 

TABLE    31. 


Temperature 
When  Laying  Track. 


At  90°  above  zero 
At  70°  above  zero 
At  50°  above  zero 
At  30°  above  zero 
At  10°  above  zero 
At  10°  below  zero 


Space  to  be  Left 
Between  Ends  of  Rails. 


1 

T15" 


i 

3 

i 

6 
T6 


of  an  inch 
of  an  inch 
of  an 
of  an 
of  an  inch 
of  an  inch 


nch. 
nch. 


To  give  to  the  track  the  proper  opening  at  the  joints, 
expansion  shims  are  used.  They  are  made  of  iron,  and 
are  of  various  forms.  A  simple  and  effective  shim  is  made 
by  bending  a  piece  of  ^-inch  iron  into  the  form  of  a  right 
angle,   as  shown   in   Fig.    498.      This   gives  a   combination 

shim  of  two  thicknesses, 
viz.,  y^^  and  |  inches. 
After  the  angle  is  formed, 
the  Y^g-inch  shim  is  ob- 
tained by  hammering 
the  ^-inch  bar  to  the  re- 
Fi«-498.  quired    thickness.       The 

thickness  of  each  shim  should  be  clearly  stamped  upon  it. 
When  put  in  place,  the  shim  reaches  the  full  depth  of  the 
head  of  the  rail,  and  the  bent  portion  lies  flat  on  the  top  of  the 
rail.     The  shims  should  not  be  removed  until  the  joint  is 


TRACK  WORK. 


1045 


full  bolted,  and  there  should  be  a  sufficient  number  of  them 
on  hand  to  keep  the  track-layers  constantly  employed,  and 
not  require  them  to  wait  until  shims  can  be  removed  from 
bolted  joints. 


SPIKING   RAILS. 

1612.  There  is  no  part  of  the  track  laying  more  likely 
to  sujffer  from  carelessness  than  the  spiking.  A  spike,  to 
be  driven  properly,  should  be  started  in  a  really  vertical 
position.  The  spikes  at  the  joints,  centers,  and  quarters  of 
the  rail  should  be  driven  first.  The  right-hand  rail  is  usual- 
ly spiked  first.  The  gauge  is  then  placed  on  the  fixed  rail, 
and  the  free  one  brought  to  the  gauge  and  spiked. 

The  common  and  slovenly  custom  of  driving  spikes  at  an 
angle  should  not  be  tolerated.  An  almost  equally  pernic- 
ious custom  is  to  drive  the  spike  with  the  track  at  loose 
gauge  and  then  bending  the  head  so  as  to  give  the  rails  their 
proper  gauge. 

First  see  to  it  that  the  free  rail  is  brought  to  the  gauge. 
Then  start  the  inside  spike  a  little  removed  from  the  base 
of  the  rail,  the  head  inclined  slightly  backwards.  Having 
started  the  spike,  a  good  blow  will  bring  it  to  a  vertical 
position,  after  which  the  blows  should  be  delivered  vertically 
upon  the  head.  The  last  blow  should  slightly  draw  the  head 
towards  the  rail  base.  AVhere  the  gauge  is  widened  on  curves, 
a  special  gauge  should  be  provided  and  the  eye  not  trusted 
to  give  the  proper  increase  in  gauge.  Spikes  should  not  be 
driven  in  the  middle  of  the  tie,  especially  in  severe  freez- 
ing weather,  as  they  are 
liable  to  split  it,  but  at 
from  2^  to  3  inches  from 
the  outside  of  the  tie, 
where  the  wood  is  sure  to 
be  sound  and  the  grain  less 
open. 

The  proper  arrangement 
of  the  spikes  in  the  tie  is 
show.n   in    Fig.   499.     Ties  spiked  in    this  fashion  can  not 


Fig.  499. 


1046 


TRACK  WORK. 


become  skewed,  and  the  track,  in  consequence,  thrown  out 
of  gauge. 

In  spiking,  the  tie  must  be  held    firmly  against  the  base 
of  the  rail.     If  from  any  cause  the  rail  does  not  lie  directly 


Fig.  500. 

upon  the  tie,  the  tie  must  be  held  against  the  rail  with  a 
nipping  bar,  shown  in  Fig.  500. 

The  ends  of  the  ties  should  be  spaced  at  a  uniform  distance 
from  the  rail,  both  for  the  sake  of  appearance  and  to  give 
to  the  rail  a  uniform  foundation.  A  gauge  made  of  hard 
wood  and  meeting  this  requirement  is  shown  at  A  and  B  in 
Fig.  501. 

The  spiker  first  places  the  gauge  upon  the  tie  with  its 
head  close  against  the  end  of  the  tie,  as  shown  at  A.     The 


Pig.  501. 

base  of  the  rail  is  then  brought  against  the  end  of  the  gauge 
and  the  inside  spike  started.  The  gauge  is  then  removed 
and  the  outer  spike  started,  and  both  driven  home.  The 
other  rail  being  spiked  to  a  proper  gauge  will  make  the  rails 
equidistant  from  the  ends  of  the  ties.  The  gauging  of  the 
ties  is  too  often  done  by  guesswork,  as  is  evinced  by  a 
ragged  line. 

1613.     Spiking  Bridge  Ties.— Holes  should  be  bored 
in  bridge  ties  to  receive  the  spikes  instead  of  driving  the 


TRACK  WORK.  1047 

spikes  directly  into  the  tie.  As  bridge  ties  are  sawed,  they 
are  often  cross-grained  and  liable  to  split  unless  holes  are 
bored  for  the  spikes.  The  diameter  of  the  spike  holes  should 
be  about  ^^  inch  less  than  the  diameter  of  the  spike,  so  that; 
in  driving,  the  hole  will  be  completely  filled  with  the  fiber  of 
the  wood. 

1614.  Pulling  Spikes. — When  a  spike  is  to  be  drawn 
from  a  tie  in  frosty  weather,  or  from  an  oak  tie  at  any  time 
of  year,  it  should  always  be  given  a  light  blow  with  a  spike 
maul  before  using  the  claw  bar.  The  blow  breaks  the  hold 
which  the  wood  has  upon  the  spike,  and  permits  of  the  spike 
being  drawn  with  safety.  Without  this  precaution  the 
spike  is  liable  to  break  off  under  the  head.  The  instrument 
for  drawing  spikes  is  called  a  cla-w  bar,  and  is  shown  in 
Fig.  503.      Its  weight  is  about  25  lb.     The  end  a  of  the  claw 


Fig.  502. 

bar  is  divided  like  the  claw  of  a  carpenter's  hammer  and  the  , 
bar  bent  into  a  goose-neck  to  increase  the  distance  through 
which  the  opposite  end  b  can  move.  In  drawing  a  spike 
care  should  be  taken  that  the  claw  is  well  under  the  spike- 
head  before  a  strain  is  put  upon  the  bar.  When  only  the 
lip  of  the  claw  is  under  the  head,  there  is  great  danger  of 
the  claw  being  broken,  especially  if  a  heavy  stress  is  put 
upon  it.  When  the  spike  is  driven  so  deeply  into  the  tie 
that  the  claw  can  not  be  forced  under  it,  the  end  b  of  the 
claw  bar,  which  is  wedge-shaped,  may  be  forced  under  the 
spike-head,  lifting  it  so  the  claw  may  be  used. 

1615.  Gauging  Tracl«. — In  track  laying,  no  part  of 
the  work  should  receive  more  careful  attention  than  the 
gauging  of  the  track.  A  track  gauge,  to  be  in  proper 
position,  must  be  at  right  angles  to  the  center  line  of  the 


1048  TRACK  WORK. 

track,  and  with  this  fact  in  view  the  gauge  shown  in  Fig. 
503  was  devised.  The  gauge  consists  of  two  U-shaped  cast- 
ings connected  bv  a  short  iron  pipe  which  is  threaded  at 
both  ends,  and  screws  into  them.  The  castings  have  lugs 
on  their  under  sides,  as  shown  at  A  and  B.  The  distance 
A  B  between  the  lugs  determines  the  gauge.  A  line  drawn 
across  the  faces  of  the  gauge  lugs  is  at  right  angles  to  a 
line  drawn  through  the  center  of  the  iron  pipe.  To  place 
the  gauge  at  right  angles  to  the  center  line  of  the  track, 
bring  both  lugs  shown  at  C  against  the  head  of  the  rail.  A 
notch  filed  in  the  gauge  at  D  marks  the  center  of  the  track. 


G 


^^  h  ~'^*^£' 


3      C 


Fig.  503. 

Never  crowd  the  gauge  in  spiking  the  rails.  Let  the  rails 
only  touch  the  gauge  marks.  Place  the  gauge  about  eight 
inches  ahead  of  the  tie  to  be  spiked.  This  places  the  gauge 
out  of  danger  of  the  spiking  hammers,  and  insures  a  perfect 
gauge.  

SURFACING  TRACK. 

1616.  As  soon  as  the  track  is  full  bolted  and  spiked,  it 
is  put  into  surface.  This  is  an  easy  matter  where  the  tics 
have  been  bedded  to  grade,  an3  requires  much  less  material 
than  where  they  have  been  placed  upon  the  roadway  and 
the  rails  spiked  to  them  without  any  attempt  at  grade.  If 
the  track  is  to  be  earth  ballasted,  the  material  is  taken 
from  the  shoulder  of  the  roadway.  If  cinders,  gravel,  or 
broken  stone  is  to  serve  as  ballast,  construction  trains 
should  furnish  the  material  as  fast  as  it  is  needed. 

Ordinarily,  earth  is  used  on  new  lines,  as  the  finances  of 


TRACK  WORK.  1049 

the  company  seldom  warrant  the  use  of  costlier  material. 
^_^T)  It  is  only  on  prairie  lines  that  sufficient  ma- 

%Jw  terial  can  be  borrowed  from  the  roadway 

IK  to  put  the  track  in  permanent  surface,  but 

ilNS  in  most  cases  enough  is  available  to  place 


Fig.  504. 


the  track  in  safe  condition  for  the  full 
operation  of  the  construction  train. 
The  tools  used  in  surfacing  are  the 
fc  track  jack,  shovel,  and  tamping  bar. 
^  The  track  jack,  which  takes  the  place 
of  the  ancient  track  lever,  is  one  of  the 
most  economical  and  indispensable  oi 
the  trackman's  tools.  One  of  the  best  track  jacks  on  the 
market  is  that  made  by  Joyce,  Gridland  &  Co.,  of  Canton, 
Ohio,  and  is  shown  in  Fig.  504. 

This  jack  is  simply  and  strongly  made.  The  foot  A  of 
the  jack  is  placed  between  the  ties  with  the  lug  B  under  the 
rail.  By  means  of  the  lever  C  the  toothed  bar  D  is  raised. 
The  lug  B  forms  a  part  of  the  bar  D,  the  two  forming  one 
casting,  and,  consequently,  in  moving  together,  carry  the 
rail  with  them.  A  tripper  £  is  so  arranged  that  if  desired 
the  bar  D  may  be  made  to  drop  instantaneously.  In  using 
the  jack  it  should  always  be  placed  on  the  outside  of  the  rail 
with  the  lever  pointing  from  the  track.  Numerous  acci- 
dents have  been  caused  by  misplaced  track  jacks,  some  of 
them  entailing  great  loss  of  life  and  property. 

The  track  is  raised  to  grade  with  the  jack,  and  the  ma- 
terial deposited  with  the  shovel.  Many  trackmen  use 
only  the  shovel  blade  in  surfacing  track  for  the  first  time, 
and  this  is  probably  the  wiser  policy,  as  the  prime  object  of 
the    first    surfacing    is    to    make    the    track   safe   for    the 


1050  .  TRACK  WORK. 

construction  train,  and  any  work  which  unnecessarily  delays 
the  construction  train  is  manifestly  unwise.  There  should 
be  no  confusion  in  the  work  as  a  result  of  changing  work. 
Each  man  should  be  assigned  to  his  special  work  and 
required  to  do  it. 

1617.  Lining  Track. — As  soon  as  the  track  has  a 
safe  surface,  it  must  be  brought  to  line.  This  is  done  with 
lining  bars,  shown  in  Fig.  505. 

In  lining,  the  trackmen  with  bars  are  placed  at  the  joints, 
quarters,  and  centers  of  the  rails  nearest   a  center  stake. 

<■  «  •        m      \\ 

<  y 

Weight,  27\(i  lb. 
Fig.  505. 

The  foreman  places  the  gauge  on  the  track  at  the  center  stake 
and  orders  the  track  thrown  until  the  center  mark  on  the 
gauge  coincides  with  the  tack  in  the  center  stake.  He  then 
moves  his  men  to  another  center  stake  and  repeats  the 
operation.  Having  placed  the  track  on  center  at  the 
stakes  for  300  or  400  feet,  he  lines  in  the  intermediate  por- 
tions by  eye.  He  should  then  check  the  line  at  the  center 
stakes  to  make  sure  that  the  track  has  not  moved  while  lin- 
ing the  intermediate  portions  by  eye.  It  is  needless  to  say 
that  if  the  ties  have  been  laid  to  a  tie  line,  the  track  will 
not  require  any  lining  until  after  the  first  surfacing. 

1618.  Final  Surfacing.  —  After  the  construction 
train  has  run  over  the  track  for  a  few  days,  the  track  will 
show  numerous  low  places,  especially  at  the  joints.  A  sur- 
facing crew  should  then  go  over  the  line,  putting  the  track 
in  good  surface.  The  material  required  for  the  final  surfa- 
cing can  be  borrowed  from  the  roadway  or  obtained  by 
widening  and  ditching  the  cuts.  That  required  for  the 
track  in  the  cuts  is  shoveled  directly  from  the  ditch  into  the 
track,  while  that  required  for  the  embankment  should  be 
hauled  by  the  gravel  train.  This  plan  is  in  every  way  bet- 
ter   than    to    borrow  the  material   from   the  embankment. 


TRACK  WORK.  1051 

The  freezing  and  thawing  of  the  following  winter  will  cause 
the  slopes  of  most  cuts  to  break  and  cave,  filling  the  ditches 
with  heavy  mud,  which  must  be  removed  to  make  the  track 
safe.  Hence,  the  removal  of  this  material  for  surfacing  at 
the  time  of  track  laying  is  practically  clear  gain 

In  the  final  surfacing,  all  ties  should  be  thoroughly  tamped. 
This  is  best  done  with  the  tamping  bar  shown  in  Fig.  506. 


Fig.  506. 

An  excellent  substitute  for  the  tamping  bar  is  the  iron- 
handled  shovel,  which  serves  both  purposes  of  the  shovel 
and  tamping  bar.  When  using  them,  the  foreman  can 
spread  out  his  forces,  giving  to  each  man  his  share  of  ties, 
and  thus  obtaining  equal  service  from  all.  When  the  ties 
are  to  be  hard  tamped,  the  tamping  bar  is  the  tool  for 
effective  service.  The  ballast  should  be  tamped  under  the 
tie,  throughout  the  entire  length,  but  hardest  at  the  points 
directly  under  the  rails,  where  the  load  is  heaviest.  In  case 
the  ballast  midway  between  rails  is  tamped  the  hardest, 
there  is  danger  of  the  ties  being  broken  in  two  at  the  middle 
by  a  heavy  train.  This  danger  is  especially  great  when  the 
ties  are  of  soft  wood. 

The  object  of  ballasting  track  is  not  only  to  secure  a  firm 
foundation  for  the  ties,  but  to  so  bed  them  that  the  track 
shall  not  be  thrown  out  of  line  by  the  lateral  thrust  of  pass- 
ing trains.  That  mode  of  ballasting  is  best  which  most  com- 
pletely beds  the  ties  and  at  the  same  time  provides  for  the 
prompt  removal  of  all  water  which  falls  upon  the  roadbed. 

In  filling  in  the  track  the  material  should  be  deposited  in 
the  middle  of  the  track  and  not  against  the  rails.  It  should 
be  raised  to  a  height  of  about  2^  inches  above  the  ties  at 
their  middle  point  A  (see  Fig.  507),  and  sloped  towards  the 
ends  of  the  ties.  Its  surface  at  the  inside  line  B  of  the  rails 
should  be  such  as  to  permit  the  shovel  to  be  passed  freely 
underneath    the    rail    between    the    ties,    and    the    slope 


1052 


TRACK  WORK. 


continued  to  the  end  of  the  tie  where  it  should  just  meet  the 
base  of  the  tie.  Outside  of  the  ties,  the  shoulder  CD  should 
continue  at  a  slope  of  1^  inches  to  the  foot  to  the  edge  of 
the  embankment. 

This  insures  complete   drainage.      Rain  falling  upon  the 

roadway  will  run  off  before  it  can  penetrate  the  ground. 

\k 8-0' 


Fig.  507. 


Provision  must  be  made  for  conducting  this  surface  water 
into  natural  channels.  This  is  accomplished  by  means  of 
side  ditches. 


DRAINAGE. 

1619.  Ditching  and  Ballasting. — All  railroad  man- 
agers and  operators  are  united  in  their  estimate  of  the  im- 
portance of  thorough  drainage.  This  can  be  effected  only 
by  a  thorough  system  of  drains  and  ditches.  These  should 
be  of  such  number  and  size  that  they  will  not  only  meet  the 
requirements  of  an  ordinary  rainfall,  but  also  of  the  heaviest 
freshets. 

Ditches  are  of  two  kinds,  viz.,  side  ditches,  those  excava- 
ted in  cuts  on  both  sides  of  the  roadway,  and  surface  ditches, 
those  excavated  above  the  slope  of  cuts  to  prevent  the  slope 
from  being  washed  down.  Side  ditches  are  partially  made 
during  the  grading  of  the  roadway;  surface  ditches  should 
always  be  completed  during  construction,  as  they  are  of  the 
first  importance  in  affording  protection  to  the  slopes  against 
the  floods  of  surface  water  which  invariably  accompany  a 
heavy  freshet.  The  water  which,  during  a  heavy  shower, 
falls  upon  the  side  slopes  and  track,  is  about  all  that  ordinary 
side  ditches  can  accommodate;  and  if  the  protection  of  sur- 
face ditches  is  lacking,  great  quantities  of  surface  water  are 


TRACK  WORK.  1053 

discharged  at  different  points  directly  upon  the  unprotected 
slopes,  soaking  the  roadbed,  carrying  with  it  quantities  of 
earth  and  gravel  which  choke  the  side  ditches,  and,  where  the 
quantity  of  water  is  sufficient,  producing  a  washout.  In  fact, 
the  surface  ditch  is  indispensable  to  a  newly  constructed 
road,  and  the  question  of  its  construction  should  not  be  open 
to  debate. 

As  stated  above,  the  side  ditches  are  partially  made  during 
the  grading  of  the  roadway,  and  their  completion  deferred 
until  the  ballasting  and  final  surfacing  of  the  track.  All  the 
material  excavated  in  completing  the  ditching  should  be  used 
in  surfacing  the  track,  and  any  additional  material  required 
should  be  obtained  by  widening  the  cuts. 

Wet,  springy  cuts  are  a  serious  annoyance  and  expense  to 
any  railroad,  especially  where  the  widths  of  roadways  and 
slopes  are  limited  by  a  fixed  standard.  A  cut  whose  width 
and  slopes  are  ample  for  sand  or  gravel  is  totally  inadequate 
for  clay.  Springs  in  the  bottom  of  the  cut  keep  it  constantly 
wet,  and  a  firm  track  is  impossible.  Frost  and  rain  cause  the 
slopes  to  cave,  filling  up  the  ditches  and  often  covering  the 
ties  from  sight.  Such  a  track  will  be  full  of  sags  in  summer 
and  badly  heaved  in  winter,  and  at  no  time  safe  for  trains  at 
high  speed.  There  is  nothing  to  be  gained  from  tinkering 
with  and  patching  up  such  a  track.  The  permanent  cure 
is  in  widening  the  cut  and  reducing  the  slopes,  so  that 
whatever  material  caves  in  will  lodge  well  outside  the  ditch 
line.  The  ditches  should  be  from  8  to  10  feet  from  the  rails, 
and  so  deep  that  the  ballast  will  not  be  soaked  by  the  water 
flowing  through  them.  The  cost  of  such  work  will  often  be 
heavy,  but  it  will  end  the  trouble  and  prevent  the  further 
wasting  of  money  in  useless  tinkering. 

During  the  construction  of  the  road,  the  slopes  and  zvidth 
of  roadivay  should,  so  far  as  possible,  be  suited  to  the  charac- 
ter of  the  material  in  which  the  excavations  are  made. 

The  dotted  lines  in  Fig.  508  show  a  standard  section  of  a 
through  cut  as  made  during  the  grading  of  the  line,  and  the 
full  lines  show  the  section  after  the  track  has  been  laid,  the 
cut  widened,  the  ditches  made,  and  the  track  ballasted.   The 


1054 


TRACK  WORK. 


material  excavated  in  this  work  is  used  for  ballasting  the 
track.  In  establishing  the  grades  for  a  new  line,  the  com- 
petent engineer  will  make  provision  for  the  drainage  of  the 
cuts.  Sometimes  the  grade  is  continuous  throughout  the 
cut,  carrying  all  the  water  one  way;  but  where  the  average 
grade  is  level,  the  drainage  is  effected  by  making  the  grade 
to  ascend  from  both  ends  of  the  cut,  uniting  them  by  an  easy 
vertical  curve  at  the  middle. 

Where  the  cut  is  short,  it  is  a  mistake  to  break  the  gradient, 
but  rather  depend  for  drainage  upon  well-constructed  ditches. 
Where  the  grade  of  the  cut  is  level,  the  ditches  at  the  middle 
of  the  cut  are  made  shallow,  and  the  depth  gradually  in- 
creased towards  the  ends.   The  grades  of  such  ditches  should 


Fig.  508. 


be  given  by  the  engineer,  and  the  excavation  made  to  con- 
form to  those  grades.  It  is  the  continuous  grade  which 
gives  to  a  ditch  its  full  efficiency.  Where  the  grade  is  a  suc- 
session  of  levels  and  sudden  drops,  the  level  places  accumu- 
late mud  on  account  of  a  sluggish  current,  and  the  steep 
places  wash  badly  because  of  a  rapid  current ;  and  in  a 
comparatively  short  time  a  new  ditch  must  be  made. 

Particular  attention  should  also  be  paid  to  the  alinement 
of  the  ditch.  Crooks  in  the  ditch  impede  the  flow  of  the 
water  and  tend  to  increase  the  deposit  of  mud.  First 
determine  the  line  of  the  ditch,  with  a  view  of  avoiding  any 
unnecessary  excavation,  and  then  cut  the  ditch  to  a  true  line. 

When  gravel  or  broken  stone  is  used  for  ballast,  the  section 
of  the  roadbed  is  somewhat  altered,  although  its  general 
dimensions  remain  the  same.  As  stated  in  Art.  1603,  the 
ties  should  not  be  bedded  when  cinders,   gravel,  or  stone 


TRACK  WORK. 


1055 


ballast  is  to  be  used.  A  section  of  roadway  ballasted  with 
either  cinders  or  gravel  is  shown  in  Fig.  509.  The  ballast  is 
filled  in  between  the  ties,  flush  with  their  tops,  and  extends 
to  a  depth  of  8  inches  below  them,  sloping  from  the  outer 
top  edge  A  of  the  tie  to  the  edge  of  the  ditch. 
•  On  some  roads  the  shoulders  at  B  and  C  are  rounded  off, 
as  shown  by  the  \m&  D  E,  before  the  ballast  is  deposited. 
The  effect  of  this    is  to  improve  the  drainage. 

The    ditch  extends   12   inches   in   depth   below  subgrade; 
i.  e.,  the  line  B  C. 

The  subgrade  is  the  grade  line  laid  down   by  the  en- 
gineers for  the  grading  of  the  roadway,  and  marks  the  bot- 


FlG.  509. 

toms  of  cuts  and  the  tops  of  embankments.  The  actual 
Q^rade  line  marks  the  elevation  of  the  top  of  the  rail,  and  is 
from  15  to  24  inches  above  subgrade.  When  gravel  or 
broken  stone  is  used  as  ballast,  the  material  excavated  in 
ditching  the  cuts  should  be  loaded  on  a  gravel  train  and  de- 
posited upon  the  embankments  wherever  needed.     The  more 


Fig.  510. 

material  deposited  on  the  embankments  the  better,  as  they 
are  bound  to  cave  more  or  less  from  the  effects  of  frost  and 
rain,  before  grass  has  grown  in  sufficient  quantities  to  pro- 
tect them. 

A  section  of  track  ballasted  with  broken  stone  is  shown  in 


1056  TRACK  WORK. 

Fig.  510.  The  ballast  extends  from  10  inches  below  the 
bottom  of  the  ties  to  the  level  of  their  tops,  and  is  shouldered 
outwards  from  the  ends  of  the  ties  as  shown  in  the  figure. 
The  side  ditches  are  12  inches  in  depth,  the  slope  of  the  bal- 
last and  that  of  the  ditch  forming  practically  a  straight  line. 
The  slopes  of  the  cuts  given  in  Fig.  510,  as  well  as  those 
given  in  Figs.  508  and  509,  are  1  horizontal  to  1  vertical 
This  is  the  steepest  slope  at  which  earth  will  stand.  The 
certain  effect  of  weather  is  to  cause  the  slope  to  cave,  flat- 
tening it  and  at  the  same  time  filling  up  the  ditches.  In  all 
recent  railroad  construction,  where  the  finances  of  the  com- 
pany will  permit,  the  slopes  of  both  cuts  and  embankments 
are  made  the  same,  viz.,  1|  horizontal  to  1  vertical.  Cuts 
can  be  widened  much  more  cheaply  before  than  after  track- 
laying,  but  it  is  often  a  difficult  question  to  decide  where  it 
is  safest  to  economize. 

The  proper  time  to  clean  ditches  is  in  the  fall,  commen- 
cing about  October  1  and  finishing  by  or  before  November  1. 
Occasionally  the  slopes  of  a  cut  cave  in  so  badly  that  ditches 
require  frequent  clearing.  The  only  permanent  cure  is  to 
widen  the  cut  to  such  an  extent  that  caving  material  can  not 
encroach  upon  the  ditches  and  track.  Some  writers  on 
track  insist  that  there  should  be  no  side  ditch  nearer  than 
10  feet  from  the  rails,  nor  slopes  less  than  1^  horizontal 
to  1  vertical.  This  would  require  a  roadway  at  least 
twenty-four  feet  in  width  for  a  single  track,  and  involve 
an  outlay  which  would  prohibit  the  building  of  nearly  all 
new  lines. 

The  roadway  and  track  sections  given  in  the  preceding 
pages  are  entirely  consistent  with  moderate  expense  and 
thorough  construction.  When  the  line  is  fully  equipped, 
traffic  connections  established,  and  business  on  a  paying 
basis,  there  will  be  ample  time  for  betterments  and  a  pros- 
pect of  money  with  which  to  pay  for  them. 

The  purpose  of  all  ditches  and  drains  is  to  convey  the 
water  to  natural  channels  and  thence  out  of  reach  of  the 
track.  In  Arts.  1461  and  1467,  mention  was  made  of 
the  common  fault  of   making  culvert  openings  too  small. 


TRACK  WORK.  1057 

They  should  be  designed  to  meet  the  requirements  of  the 
severest  storms  and  freshets.  At  all  low  places  where  the 
water  remains  standing  alongside  the  track,  open  culverts 
should  be  built,  allowing  the  free  passage  of  the  water. 
Brooks  liable  to  overflow  and  wash  the  track  should  have 
their  channels  deepened  or  their  banks  raised.  After  every 
freshet,  all  water  passages  should  be  thoroughly  examined 
and  all  obstructions,  such  as  sticks,  brushwood,  weeds, 
etc.,  removed.  Brush  and  weeds  not  only  obstruct  the 
passage  of  water,  but,  when  dry,  are  easily  ignited  by  sparks 
from  the  engine  and  are  a  continual  menace  to  the  safety  of 
the  track. 

Open  passages  for  water,  built  of  framed  timber,  are  to  be 
condemned.  They  are  likely  to  be  undermined  by  a  freshet, 
and  are  at  best  a  cause  for  anxiety.  If  stone  is  not  avail- 
able, the  track  should  be  carried  on  piles.  The  bents  of 
piles  next  the  embankment  should  be  sheathed  up  with  plank 
to  prevent  the  washing  of  the  embankment. 

1620.  Side  Tracks.  — The  opinion  still  prevails  on 
some  roads  that  any  kind  of  work  or  material  will  answer 
for  a  side  track.  This  is  entirely  wrong.  The  same  skill, 
work,  and  materials  that  go  into  the  main  track  should  be 
expended  upon  all  side  tracks.  The  tax  upon  trainmen  and 
rolling  stock  is  always  greater  on  side  tracks  than  on  the 
main  line,  and  it  is  there  that  time  is  either  saved  or  lost. 
With  a  good  track,  shippers  can  move  a  loaded  car  with  a 
team;  whereas,  if  the  track  is  rough,  they  are  compelled  to 
wait  for  a  freight  train,  which  must  stop  until  the  car  can 
be  shifted.  It  is  admissible  to  use  No.  2  ties  in  a  side  track, 
except  that  all  joint  ties  should  be  strictly  first-class.  Where 
No.  2  ties  are  used  they  should  be  placed  closer  together  in 
the  track,  so  as  to  insure  a  first-class  foundation  for  the 
rails.  All  side  tracks  should,  as  far  as  possible,  have  a 
switch  at  both  ends.  This  permits  trains  to  enter  the  side 
track  from  both  directions  without  passing  a  switch  and 
backing  into  the  siding;  it  also  effects  a  saving  of  time, 
labor,  and  fuel. 


1058  TRACK  WORK. 

CARE     AND    MAINTENANCE  OF  TRACK. 


SPRING  TRACK  WORK. 

1621.  At  the  first  break  up  of  winter  the  spring  track 
work  begins.  The  section  foreman  should  plan  his  work  so 
as  to  take  advantage  of  each  day  as  the  season  advances. 
As  soon  as  the  snow  has  disappeared  from  the  track,  which 
will  always  be  a  "few  days  earlier  than  from  less  exposed 
places,  he  should  set  his  men  to  work  at  cleaning  up  the 
station  grounds  and  yard.  All  scattering  track  material 
should  be  collected  and  neatly  piled  at  a  place  convenient  to 
the  hand-car  house.  All  rubbish  which  may  have  accumulated 
during  the  winter  must  be  removed  and  used  either  to  fill  up 
low  places  in  the  right  of  way,  or  burned,  if  necessary. 

All  switches  should  be  thoroughly  repaired  and  put  in  per- 
fect line.  Battered  rails  should  be  replaced  by  good  ones; 
guard-rails  and  frogs  examined  and  defects  in  them  rem- 
edied, and  all  ties  collected,  loaded  on  cars,  and  distributed 
along  the  section,  where  they  will  be  ready  at  hand  when 
needed  to  put  in  the  track.  All  breaks  in  fences  should  be 
repaired  at  the  earliest  opportunity.  The  approaches  to 
highway  crossings  should  be  made  safe,  and  everything  done 
in  the  way  of  repairs  which  the  season  will  permit  of.  As 
the  frost  begins  to  leave  the  track,  settlement  commences, 
and  the  track  should  be  carefully  watched,  thick  shims  being 
replaced  by  thinner  ones  as  the  settlement  goes  on,  and  all 
shims  removed  as  soon  as  it  is  possible  to  spike  the  rails  to 
their  proper  surface. 

Every  joint  throughout  the  section  should  be  examined; 
all  loose  bolts  tightened ;  nut-locks  or  washers  supplied 
where  needed,  and  broken  bolts  replaced  by  new  ones.  As 
the  frost  leaves  the  track,  especially  in  wet  cuts,  soft  places 
will  appear.  These  must  be  reported  to  the  train  dispatcher 
at  once.  By  keeping  the  side  ditches  clear  and  deepening 
them  as  the  frost  leaves  the  ground,  soft  places  can  usually 
be  made  safe  until  the  ground  settles,  when  thorough  re- 
pairs should  be  made.   If  the  place  becomes  dangerous  the  fact 


TRACK  WORK.  1059 

must  be  reported  by  telegraph  to  the  roadmaster,  who  will  fur- 
nish the  necessary  men  and  materials  to  make  the  track  safe. 

1622.  Washouts. — The  melting  snow  together  with 
the  spring  rains  greatly  increase  the  volume  of  surface 
water,  and  as  the  frost  comes  out  of  the  ground  but  slowly, 
ditches  and  natural  water  channels  are  taxed  to  their  utmost 
capacity.  It  is  at  this  season  of  the  year  that  washouts  and 
landslides  are  chiefly  to  be  feared.  All  ditches,  culverts,  and 
bridges  must  be  kept  clear  of  obstructions,  and  the  track 
watched  night  and  day  so  long  as  danger  is  to  be  appre- 
hended. In  case  of  a  severe  storm,  the  section  foreman 
should  send  a  responsible  man  to  one  end  of  the  section  with 
the  proper  signals  to  stop  trains  in  case  of  danger,  while  he 
goes  to  the  other  end  of  the  section,  leaving  a  man  to  guard 
any  dangerous  spot  until  the  section  is  entirely  covered.  In 
case  he  laches  the  means  to  repair  any  damage  done,  he  must 
report  the  fact  by  telegraph  to  both  the  train  dispatcher  and 
roadmaster,  in  order  that  the  former  may  hold  trains  at 
convenient  points  while  the  latter  can  rush  a  construction 
train  through  to  the  point  of  danger.  The  foreman  should 
include  in  his  report  the  location  of  the  break  or  washout, 
the  number  of  the  bridge  or  culvert,  the  length  of  thebreak,^ 
the  number  of  missing  bents,  and  any  information  which 
will  aid  the  roadmaster  in  making  a  Correct  estimate  of  the 
men  and  materials  necessary  to  repair  the  damage.  He  can 
then  set  to  work  with  his  men,  making  such  repairs  as  his 
limited  force  will  permit  of,  and  being  ready  to  render  every 
assistance  in  his  power  to  the  roadmaster,  who  assumes 
charge  on  his  arrival.  A  foreman  should  never  attempt  any 
repairs  of  track  until  he  has  inspected  his  entire  section,  as 
two  or  more  breaks  may  occur  simultaneously,  and  while  re- 
pairing one  break  an  accident  is  liable  to  occur  at  another. 

1623.  Repairs  of  Track. — As  soon  as  the  frost  has 
left  the  track  and  all  shims  have  been  removed,  bringing 
the  rails  down  to  the  surface  of  the  ties,  the  section  foreman 
should  go  rapidly  over  his  section,  making  such  repairs  as 
will  render  the  track  safe  and  reasonably  smooth.     If  the 


1060  TRACK  WORK. 

track  is  well  ballasted  with  gravel  or  broken  stone  these  re- 
pairs will  be  quickly  made,  as  such  track  will  hold  a  good 
line  and  surface  after  the  severest  winter.  If,  however,  the 
ballast  is  clay,  the  track  will  show  many  low  places  and  an 
uneven  line.  The  track  jack,  shovels,  and  picks  are  all  the 
tools  needed  for  the  first  repairs.  A  man  is  set  to  dig  block 
holes  for  the  jack  at  the  lowest  points  in  the  sags.  The 
track  is  then  raised  until  it  is  in  average  surface  with  the 
track  at  either  end  of  the  sag.  Dirt  is  then  shoveled  under 
the  ties,  care  being  taken  to  throw  it  well  back  to  the  middle 
of  the  tie.  No  attempt  should  be  made  to  tamp  the  ties  other 
than  to  fill  up  the  cavities  formed  by  raising  them.  A  part 
of  the  force  will  follow,  dressing  up  the  track  and  filling 
block  holes.  The  foreman  should  stop  raising  track  about  two 
hours  before  quitting  time,  taking  with  him  sufficient  hands 
to  line  up  and  gauge  the  track  surfaced  during  the  day. 
The  line  side  of  the  track  is  then  given  a  perfect  line. 
Either  rail  may  be  taken  as  the  line  side,  but  the  same  rail 
should  always  be  used  for  lining.  A  part  of  the  force  take 
the  gauge  and  spike  maul  and  spike  the  track  to  gauge, 
while  the  rest  follow,  dressing  up  the  track.  This  work  will 
put  the  track  in  perfect  line  and  fair  surface,  and  by  the  time 
the  entire  section  is  covered  the  ground  will  be  thoroughly 
settled  and  the  track  in  shape  for  permanent  surfacing. 

1624.  Lining  Track. — When  lining  track  the  fore- 
man should  stand  with  his  back  to  the  sun  and  as  far  from 
the  piece  of  track  which  he  is  to  line  up  as  his  eyesight  will 
permit.  This  gives  him  a  better  view  of  the  straight 
portions  on  each  side  of  the  crooked  portion,  all  three  of 
which  are  to  be  brought  into  the  same  straight  line.  A 
simple  device,  much  practiced  by  trackmen  when  lining 
track,  is  to  place  small  lumps  of  dirt  on  the  top  of  the  rail 
to  be  straightened.  These  lumps  show  plainly  in  contrast 
to  the  bright,  unbroken  surface  of  the  rail,  and  when 
brought  into  range  insure  a  good  line. 

With  a  strong  section  gang  the  foreman  can  readily  per- 
form any  of  the  tasks  which  confront  him ;  but  when  from 


TRACK  WORK.  1061 

necessity  his  force  is  reduced  to  a  minimum,  he  is  obHged  to 
resort  to  every  expedient  within  his  knowledge.  He  must 
not  only  direct  the  work,  but  lead  in  its  execution.  Fre- 
quently a  foreman  will  have  charge  of  ten  miles  of  track, 
and  have  but  four  hands  besides  himself  wherewith  to  main- 
tain it.  It  is  under  such  circumstances  that  ingenuity  and 
energy  count  at  their  full  value. 

When  a  sag  in  the  track  has  caused  a  crook  in  the  line,  and 
there  is  not  sufficient  force  to  throw  the  track  to  line,  the 
following  scheme  will  enable  the  foreman  to  straighten  the 
track  and  hold  it  in  place.  He  can  only  straighten  one  rail 
length  at  a  time,  and-to  do  that  he  should  remove  the  spikes 
from  three  or  four  of  the  ties  under  the  rail.  The  ties  so 
detached  from  the  rail  are  called  dead  ties.  The  lining 
bars  are  then  placed  under  the  rail  upon  the  dead  ties,  which 
afford  a  far  firmer  foundation  and  leverage  than  ordinary 
ground.  The  track  is  then  thrown  to  line,  after  which  the 
dead  ties  are  shifted  to  their  proper  position.  If  the  track 
has  a  tendency  to  slip  back  out  of  the  line,  the  rails  can  be 
temporarily  spiked  to  the  dead  ties,  which,  being  securely 
bedded,  will  hold  the  rails  permanently  in  place. 

1625.  Straining  of  Track  Bolts. — Reference  has 
already  been  made  to  this  serious  fault,  which  is  almost 
universal  among  trackmen  and  generally  due  to  ignorance 
on  their  part.  The  rail  splices  on  most  American  roads  are 
fitted  with  nut  locks  of  either  metal  or  fiber,  the  object  of 
which  is  to  lock  the  nut  and  at  the  same  time  permit  of  the 
expansion  and  contraction  of  the  rail.  In  order  that  expan- 
sion and  contraction  may  take  place,  the  nut  should  only  be 
brought  to  a  snug  bearing  on  the  nut-lock,  whereas,  the 
common  practice  is  to  screw  on  the  nuts  as  far  as  the  strength 
of  the  trackman  will  permit.  This  places  the  bolt,  nut-lock, 
and  nut  under  a  severe  strain,  with  the  result  that  the  rail 
can  not  freely  expand  and  contract;  the  nut-lock  is  deprived 
of  all  power  to  act,  and  at  the  first  abrupt  change  of  tem- 
perature the  nuts  are  liable  to  snap  off  on  account  of  the 
sudden  strain.  One  of  the  first  duties  of  the  section  fore- 
man is  to  explain  to  his  men  the  object  of  the  slots  in  the 


10G2  TRACK  WORK. 

rails,  expansion  shims,  and  nut-locks.  In  putting  in  track 
bolts,  first  bring  the  nut  to  a  bearing,  after  which  a  half 
turn  with  the  wrench  is  sufficient.  Track  wrenches  should 
not  be  longer  than  16  inches  for  f-inch  bolts.  Spike  slots 
should  always  be  made  in  the  angle  splice.  These  prevent 
the  creeping  of  the  rails  and  at  the  Same  time  permit  the 
free  expansion  and  contraction  of  the  rails. 

1626.  Removing  Old  Track  Bolts. — In  removing 
old  track  bolts  they  should  never  be  battered  with  either 
hammer  or  wrench.  The  nut  should  not  be  entirely  re- 
moved from  the  bolt  until  the  bolt  is  loosened  in  the 
splice.  When  the  nut  is  nearly  off  the  bolt,  give  it  a 
slight  tap  with  the  track  wrench.  This  will  loosen  the  bolt 
without  injuring  the  thread.  The  thread  of  the  old  bolts 
should  be  oiled  and  the  nuts  well  screwed  on  so  that  they 
will  be  complete  and  in  readiness  for  service  when  needed. 

1627.  Loose  Track  Bolts. — Changes  of  temperature 
often  cause  the  loosening  of  track  bolts.  These  are  most 
noticeable  in  the  spring  and  fall  of  the  year.  Trackmen 
should  watch  for  and  promptly  tighten  all  loose  track  bolts, 
as  they  are  one  of  the  main  causes  of  low  joints. 

1628.  Line  and  Surface  of  Bridge  Approaches. 

— Special  care  should  be  taken  to  make  the  line  and  surface 
of  the  track  on  bridge  approaches  as  nearly  perfect  as  pos- 
sible. Pile  bridges  are  liable  to  heave,  especially  when  the 
ice  surrounding  them  is  lifted  by  a  spring  freshet.  Section 
men  should  not  attempt  to  repair  bridges  unless  circum- 
stances require  it.  They  have  neither  the  experience  nor 
tools  for  such  work. 

Bank  sills  (those  resting  upon  the  embankment  and 
supporting  bridge  stringers)  are  continually  settling,  and 
cause  a  bump,  or  lift,  in  the  track  at  the  bridge  line.  The 
sills  should  be  raised  and  kept  in  perfect  surface  by  hard 
tamping,  and  all  bank  ties  kept  well  tamped.  If  possible, 
avoid  placing  a  rail  joint  over  a  bank  sill.  It  is  almost  cer- 
tain to  be  low  at  times;  but. rather  arrange  the  track  so  as 
to  bring  the  center  of  the  rail  at  that  point. 


TRACK  WORK.  1063 

SUMMER  TRACK  WORK. 

1629.  General  Repairs. — On  Northern  railroads, 
general  track  work  commences  with  the  month  of  May.  By 
that  time  all  frost  has  left  the  track  and  settlement  has 
taken  place  generally. 

The  section  foreman  should  go  to  the  end  of  his  section 
to  commence  track  repairs,  and  work  towards  home,  finish- 
ing as  he  goes,  raising  all  small  sags  and  low  joints  to 
a  proper  surface,  tightening  all  loose  bolts,  relining  the 
track,  and  correcting  all  defects  in  gauge.  He  should  fill 
in  the  middle  of  the  track  and  dress  it  down  to  the  track 
shoulder.  He  should  allow  nothing  short  of  actual  com- 
pulsion to  call  him  from  his  work  until  the  entire  section 
is  covered.  He  will  then  be  in  readiness  to  put  in  new 
ties,  lay  new  steel,  surface  track,  or  cut  weeds  according 
as  the  work  demands.  In  going  over  the  track,  the  fore- 
man can  correctly  estimate  the  number  of  new  ties  needed 
and  make  early  requisition  for  them  in  order  that  they 
may  be  on  hand  when  needed.  He  should  keep  a  record 
of  the  places  where  new  ties  are  needed  and  distribute  them 
accordingly. 

1630.  Track  Ties. — Track  ties  constitute  one  of  the 
most  important  items  in  the  initial  cost  and  maintenance  of 
a  railroad.  The  company  should  provide  the  best  ties 
within  their  means,  and,  if  possible,  have  them  well  seasoned 
before  being  placed  in  the  track.  Ties  made  from  logs  split 
in  two  parts  should  be  laid  with  the  sap  side  up.  This 
brings  the  wide  or  heart  side  of  the  tie  underneath,  which 
is  the  position  it  would  naturally  take.  Pole  ties,  those 
made  from  young  trees,  are  more  lasting  than  those  made 
from  large  logs,  as  the  older  the  tree,  the  more  open  and 
brittle  the  timber.  Sawed  ties  are  usually  smaller  than 
hewn  ties.  They  are  also  often  cross-grained,  and  hence 
more  easily  broken.  Tie  specifications  should  always 
require  uniformity  in  length  and  thickness  and  the  removal 
of  all  bark.  Tie  inspectors  should  strictly  enforce  these 
specifications.       Tie    contractors    are    quick    to   note  any 


1064  TRACK  WORK. 

laxness  in  the  enforcement  of  specifications  and  always  ready 
to  take  advantage  of  it. 

Ties  in  the  roadbed  should  be  not  less  than  8  feet  in 
length,  7  inches  in  thickness,  and  show  at  least  7  inches  of 
face  and  be  hewn  to  a  uniform  thickness  throughout  their 
entire  length.  Winding  ties  should  be  promptly  rejected. 
They  are  dear  as  a  gift. 

The  life  of  a  tie  depends  not  only  upon  the  kind  and 
quality  of  its  timber,  but  also  upon  the  weight  of  the  rails, 
condition  of  the  roadbed,  and  much  upon  the  climate.  In 
Northern  latitudes,  decay  is  almost  entirely  suspended  dur- 
ing the  late  fall  and  winter  months,  while  in  Southern 
latitudes  decay  goes  on  almost  uninterruptedly  throughout 
the  year.  The  yellow  pine  ties  of  the  South  are  best  fitted 
to  withstand  the  effects  of  the  climate,  and  when  of  sound 
heart  timber  they  are  fairly  lasting. 

The  loss  sustained  from  the  use  of  inferior  ties  is  apparent 
when  one  considers  the  cost  of  repairs  and  renewals.  A 
track  laid  on  ties  with  an  average  life  of  8  years,  and  cost- 
ing 60  cents  each,  is  vastly  more  economical  than  a  track 
laid  on  ties  with  an  average  life  of  5  years  and  costing  40 
cents  each.  The  track  laid  on  the  more  expensive  ties  will 
be  superior  from  the  start  to  that  laid  on  cheaper  ones,  and, 
besides  requiring  far  less  repairs,  it  will  be  in  good  condition 
when  the  cheap  track  must  be  entirely  rebuilt.  The  break- 
age of  spikes  and  angle  splices  is  much  greater  where  cheap 
ties  are  used,  and  accidents  more  frequent  and  severe. 

1631.  Placing  New  Ties  in  Traclc. — When  renew- 
ing ties,  no  more  material  should  be  removed  from  the 
track  than  is  necessary  to  allow  the  new  tie  to  go  into  its 
proper  place.  Where  the  track  is  mud  ballasted,  remove 
the  dirt  from  the  sides  and  from  the  ends  of  the  tie  to  a 
depth  a  little  below  its  bed,  but  without  disturbing  the  bed 
of  the  old  tie.  If  two  ties  side  by  side  need  renewal,  a 
single  trench  between  them  will  serve  for  removing  both. 
Remove  the  spikes  and  spring  the  rail  up  from  adjoining 
ties,  slipping  a  spike  under  it.     Then  knock  an  old  tie  into 


TRACK  WORK.  1065 

the  trench  and  pull  it  out.  Pull  the  new  tie  into  the  trench 
from  the  opposite  side  of  the  track  and  have  two  men  slide 
it  into  place,  keeping  it  well  up  against  the  rail  until  it  is  in 
place.  If  the  track  is  low,  throw  some  fine  dirt  under  the 
tie  and  spike  the  tie  to  the  rail.  The  ballast  removed  in 
putting  in  additional  ties  should  be  thrown  into  the  trenches 
made  when  removing  the  first  ties.  When  all  the  rotten 
ties  are  removed  from  one  rail  length,  fill  in  and  dress  the 
track  before  beginning  on  another  rail  length.  If,  after  the 
ties  are  in  place,  the  track  proves  to  be  a  trifle  high,  the 
defect  will  disappear  after  the  passage  of  a  loaded  train. 
This  method  of  putting  in  new  ties  does  away  with  most  of 
the  labor  of  tamping,  and  the  work  is  better  done.  A  gang 
can  put  in  from  one-quarter  to  one-third  more  ties  in 
this  way  than  by  any  other  method,  but  it  is  restricted  to  a 
mud-ballasted  track  alone.  If  the  ballast  is  gravel  or 
broken  stone,  all  new  ties  must  be  tamped.  The  tie  must 
be  held  up  against  the  rail  with  a  bar  while  it  is  spiked,  and 
the  ballast  thoroughly  tamped  with  a  tamping  bar.  All 
new  ties  must  be  placed  square  across  the  track,  and  if  the 
old  ones  are  too  widely  spaced,  additional  ties  must  be  put 
in  the  track  with  selected  ones  at  the  joints.  Never  spring 
the  rails  off  the  ties  on  stone  or  gravel-ballasted  tracks,  as 
the  ballast  collects  under  the  base  of  the  rail  and  prevents 
its  proper  bearing  upon  the  ties. 

The  prime  object  of  track  repairs  is  to  make  the  track 
safe,  and  if  some  parts  of  the  section  are  more  needy  than 
others,  the  foreman  should  first  make  those  places  safe  and 
then  go  ahead  with  continuous  repairs. 

1632.     Estimating    New    Ties  for  Repairs. — The 

proper  time  for  estimating  the  number  of  new  ties  needed 
for  repairs  is  in  the  fall  of  the  year.  In  the  Northern  States 
the  winter  is  the  proper  season  for  manufacturing  ties,  and 
most  tie  contracts  are  let  in  that  season.  If  the  estimates 
are  made  up  and  sent  in  to  the  roadmaster  in  the  fall,  he 
can  make  more  favorable  contracts  and  be  sure  of  having  a 
supply  when  needed. 


1066 


TRACK  WORK. 


In  making  his  estimate,  the  foreman  should  walk  over  his 
entire  section,  testing  every  tie  of  which  he  is  in  doubt  and 
reporting  the  actual  number  needed,  and  no  more.  The 
renewing  of  ties  is  one  of  the  great  items  of  cost  in  the 
maintenance  of  a  railroad,  and  a  careful  foreman  can  do 
much  towards  prolonging  their  life. 

1 633.  Disposition  of  Old  Ties. — All  labor  spent  in 
handling  old  ties  is  unremunerative,  but  they  must  be  dis- 
posed of.  In  sections  where  timber  is  scarce  they  can 
usually  be  sold  for  fuel.  If,  however,  fuel  is  abundant  and 
cheap,  the  best  way  to  dispose  of  them  is  to  burn  them. 

1634.  Tie  Account. — The  foreman  should  keep  an 
accurate  tie  account,  which  will  show  at  once  the  number  of 
ties  received,  put  in  the  track,  and  on  hand.  The  following 
is  a  good  form  for  tie  accounts: 

TIE  ACCOUNT  FOR  ONE  YEAR. 


Months. 

Ties  Received. 

Ties  Put  in 
Track. 

Ties  on  Hand. 

Hard 
Ties. 

Soft 
Ties. 

Hard 
Ties. 

Soft 
Ties. 

Hard 
Ties. 

Soft 
Ties. 

January  

February.  ...... 

March 

1,000 
800 

400 
300 

1,000 

1,800 

1,400 

800 

400 

700 

April 

400 
600 
800 

100 
400 
200 

600 

Mav 

200 

/ j 

June 

Tulv 

August 

September 

October 

November 

December 

TRACK  WORK. 


1067 


1635.  Cutting  Weeds. — On  all  mud-ballasted  roads 
the  cutting  of  weeds  is  an  important  item  in  the  cost  of 
track  repairs.  All  weeds  within  a  distance  of  3^  feet  from 
the  rail  should  be  kept  cut  clean  to  the  surface  of  the  ground. 
It  is  important  to  prevent  their  getting  an  early  start; 
hence,  when  making  track  repairs  early  in  the  spring  the 
surface  of  the  ground  should  be  shaved  over  either  with  a 
shovel  or  weed  cutter.  This  will  increase  the  labor  of  early 
track  repairs,  but  it  will  save  much  subsequent  labor  and 
loss  of  time. 

A  heavy  growth  of  weeds  seriously  checks  the  speed  and 
efficiency  of  a  train,   especially  on  heavy  grades,  besides 


FIG.  511. 


promoting  decay  of  ties.  For  cutting  weeds  the  blades  of 
shovels  or  weed  cutters  should  be  ground  to  an  edge,  and  a 
file  kept  handy  for  resharpening.  The  men  should  be  dis- 
tributed one  to  each  rail  length  to  prevent  crowding  and 
insure  an  equal  share  of  work  from  each. 

The  weed  cutter  shown  in  Fig.  511  does  inore  effective 
work,  and  is  less  severe  upon  the  men  than  the  shovel. 

The  handle  of  the  weed  cutter  is  considerably  longer  and 
the  blade  lighter  than  that  of  the  ordinary  track  shovel.  In 
using  the  weed  cutter,  men  are  not  compelled  to  keep  their 
backs  continually  bent  as  when  using  the  shovel,  and  they 
can  cover  from  one-sixth  to  one-fourth  more  ground  in  a 


day. 


1068  TRACK  WORK. 

1636.     Mowing  Weeds,  Grass,  and  Brush. — If  the 

section  force  will  admit  of  it,  all  weeds,  grass,  and  brush 
should  be  cut  from  the  right  of  way.  This  work  should  be 
commenced  by  July  20th,  mowing  first  the  grass  and  weeds 
about  all  wooden  structures  and  burning  them  as  soon  as 
they  are  dry  enough.  This  forms  a  barrier  against  fire,  and 
insures  the  safety  of  these  structures  while  burning  other 
brush  or  weeds  along  the  right  of  way.  If  possible,  mow 
the  entire  right  of  way,  burning  the  grass  and  brush  as  fast 
as  they  are  dry  enough.  With  the  right  of  way  clear  of 
combustible  matter  there  is  comparatively  small  danger  of 
fire  being  communicated  to  adjoining  property.  This  as- 
surance is  well  worth  the  cost  of  the  work,  and  it  is  well 
known  that  by  keeping  the  right  of  way  clear  of  weeds  and 
brush,  grass  is  induced  to  grow,  which  is  far  easier  to  keep 
in  order  than  brush  or  weeds. 


^^ORK   ON   OLD  TRACK. 

1 637.  Combination  Ballast. — A  track  can  be  better 
ballasted  with  a  combination  of  stone  and  gravel  than  with 
either  of  these  materialsseparately.  Each  material  has  ad- 
vantages peculiar  to  itself.  Stone  is  more  solid,  more  open, 
and  heavier  than  gravel,  and,  hence,  better  suited  to  form 
the  foundation  of  the  track  where  solidity  and  drainage  are 
of  first  importance.  Gravel  is  more  abundant,  more  elastic, 
and  much  easier  handled  than  stone.  It  does  not  wear  the 
ties,  rails,  and  rolling  stock  like  stone,  and  is  comparatively 
free  from  weeds,  and,  hence,  is  well  suited  to  form  the  top 
course  of  ballast.  Where  stone  is  used  only  for  the  founda- 
tion of  the  ballast,  it  need  not  be  broken  so  finely  as  when 
composing  the  entire  roadbed. 

Two  carloads  of  gravel  to  a  30-foot  rail  length  will  make 
a  first-class  track  where  there  is  a  foundation  of  stone 
12  inches  in  depth. 

1638.  Preparing    Old    Track    for    Ballasting:. — 

When  old  track  is  to  be  newly  ballasted  with  stone,  gravel, 
or  cinders,  all  dirt  should  be  removed  from  between  and  from 
the  ends  of  the  ties  down  to  the  base  of  ties  and  placed  on 


TRACK  WORK.  1069 

the  shoulder  of  the  roadbed.  This  will  considerably 
strengthen  the  roadbed  and  afford  a  support  to  the  ballast. 
The  engineer  should  set  grade  stakes  50  feet  apart,  giving 
the  elevation  of  top  of  rail  for  the  finished  track.  Where 
sags  occur,  if  it  is  intended  to  fill  them,  the  material 
necessary  for  raising  the  track  should  be  delivered,  and  the 
track  raised  to  the  required  grade  before  the  ballasting  is 
begun. 

1 639.  Reserve  the  Best  Ballast  for  Cuts. — When 
gravelis,  the  best  available  ballast,  and  that  of  inferior  quality, 
select  the  cleanest  gravel  for  the  cuts,  where  drainage  is  most 
difficult  and  the  track  most  affected  by  tlie  frost.  All  mud 
ballast  removed  from  the  roadbed  in  cuts  should  be  deposited 
upon  the  adjacent  embankments,  which  are  constantly  being 
reduced  in  width  by  the  action  of  rain  and  frost.  If  the  bal- 
last is  a  mixture  of  gravel,  sand,  and  loam,  it  should  be 
raised  a  full  3  inches  above  the  tie  at  the  center  of  the  track 
and  carried  out  flush  with  the  tops  of  the  ends  of  the  ties. 
All  gravel  beds  contain  streaks  of  clear  gravel.  With  a  little 
care  and  calculation  the  clean  gravel  can  be  loaded  on  sep- 
arate cars  and  the  train  made  up  with  the  selected  cars  by 
themselves.  The  inferior  ballast  should  be  unloaded  on  the 
embankment  and  the  selected  ballast  deposited  in  the  adja- 
cent cuts.  Make  the  track  shoulders  of  equal  weight.  Track 
with  unequal  shoulders  is  sure  to  work  out  of  line. 

Embankments  should  be  made  at  least  14  feet  in  width  at 
the  top  before  depositing  the  gravel  ballast,  and  16  feet  in 
width  if  the  means  of  the  company  will  permit.  With  a 
16-foot  embankment  there  is  no  loss  of  ballast  from  its  being 
crowded  over  the  shoulder. 

1640.  Ballast  Required  for  a  Mile  of  Track. — 

Allowing  an  average  length  of  33  feet  per  car,  160  cars  will 
cover  1  mile  of  track.  If  the  trains  average  8  cubic  yards 
per  car,  they  will  form  a  continuous  bed  12^  feet  in  width  at 
bottom,  12  feet  in  width  at  top,  and  6  inches  in  thickness. 
Of  this  amount  it  will  require  about  one-half  to  fill  in  between 
the  ties  and  dress  the  middle  of  the  track.     This  will  leave 


1070  TRACK  WORK. 

a  bed  of  3  inches  beneath  the  ties.  By  unloading  two  cars 
in  a  place,  the  depth  of  the  ballast  under  the  ties  is  increased 
to  8^  inches,  which  will  make  a  first-class  track,  providing 
the  subgrade  is  compact  and  thoroughly  drained. 

Gravel  may  be  loaded  at  the  pit  for  75  cents  per  car, 
making  the  cost  per  mile,  2  cars  to  a  rail  length,  about  $250. 
Under  favorable  conditions,  gravel  can  be  loaded  with  a  steam 
excavator  for  considerably  less  than  the  above  figures. 

1641.  Gravel  Pits. — The  cost  of  loading  gravel  at 
the  pit  depends  largely  upon  the  manner  in  which  the  exca- 
vation is  conducted.  The  prerequisite  for  cheap  loading  is 
a  long,  high,  and  regular  working  face.  In  laying  out  a 
track  to  a  gravel  pit,  the  ground  should  be  well  considered 
and  the  track  placed  so  as  to  meet  the  above  conditions  for 
loading.  The  switch  should  be  so  placed  that  the  turn-out 
curve  is  passed  before  the  gravel  pit  is  reached.  If  the  face 
of  the  gravel  bed  is  uneven  at  the  start,  commence  loading 
at  the  projecting  points  and  continue  until  the  face  is  uni- 
form. With  each  movement  of  the  track,  excavate  deeper  if 
the  depth  of  the  gravel  will  permit,  and  so  increase  the  height 
of  the  working  face.  Gravel  is  generally  overlaid  with  a 
layer  of  earth.  This  earth  mixes  with  the  gravel  in  loading, 
and  the  proportion  of  earth  grows  less  as  the  height  of  the 
working  face  increases.  The  grade  of  the  track  should  be 
made  as  uniform  as  possible,  and  the  track  maintained  in 
such  order  that  an  engine  may  draw  a  full  train  load  from 
the  pit.  Under  fair  conditions,  10  loaded  cars  constitute  a 
train.  If  a  steam  excavator  is  being  used,  there  should  be 
enough  cars  on  hand  to  keep  the  machine  constantly  em- 
ployed. The  empty  cars  should  be  placed  on  a  spur  track, 
connecting  with  the  track  leading  to  the  pit,  and  shifted  by 
teams  as  they  are  needed.  When  a  train  of  empty  cars  is 
returned  to  the  pit,  the  cars  are  switched  to  the  spur  track, 
and  the  loaded  train  hauled  out. 

1642.  RalsinR  Track. — When  raising  a  track  to  a 
surface,  the  following  method  is  recommended:  Take  a 
piece  of  board  1  by  4  inches  and  5  feet  in  length.     Cut  two 


TRACK  WORK.  1071 

notches,  each  3  inches  deep,  to  fit  over  the  rails,  the  space 
between  the  notches  being  equal  to  the  gauge  of  the  track. 
Place  this  sighting  board  at  a  high  place  in  the  track,  from 
8  to  10  rail  lengths  ahead  of  the  point  where  you  intend  to 
commence  track  raising.  Shim  up  the  sighting  board  to  a 
perfect  level,  giving  it  the  same  height  to  which  the  top  of 
the  rail  is  to  be  brought  in  the  raising.  Then,  go  to  the 
point  where  you  intend  to  commence  track  raising  and  lift 
the  track  to  a  proper  height,  bringing  both  rails  to  the  same 
level.  The  spirit  level  is  then  laid  aside  and  the  intervening 
track  brought  to  a  surface  by  sighting.  When  sighting, 
stand  from  50  to  75  feet  from  the  track  being  raised.  Raise 
and  tamp  each  joint  about  \  inch  higher  than  the  actual 
surface.  In  raising,  two  jacks,  a  heavy  and  a  light  one, 
should  be  used,  the  heavy  one  to  raise  the  joints,  and  the 
light  one  to  raise  the  centers  of  the  rails.  Do  not  attempt 
to  raise  a  rail  center  until  the  jack  is  in  place  at  the  next 
joint,  and  then  raise  together.  This  prevents  the  springing 
of  the  rails  and  insures  a  smooth  surface. 

By  sighting  in  -the  rails,  a  more  uniform  surface  is  ob- 
tained, and  the  delay  occasioned  by  the  repeated  use  of  the 
spirit  level  is  avoided.  When  the  sighting  board  is  reached, 
it  is  removed,  and  the  track  brought  up  to  the  proper 
surface  by  sighting. 

In  sighting  in  a  curved  track,  sight  along  the  inside  of 
the  rails.  This  permits  of  longer  and  better  sights.  The 
foreman  should  know  the  time  when  each  regular  train  is 
due,  and  have  the  track  safe  for  its  passage.  This  is  accom- 
plished by  a  run  off,  extending  from  the  new  to  the  old 
surface.  This  should  be  30  feet  in  length  for  each  G  inches 
of  difference  of  elevation  between  the  old  and  new  track 
surface. 

The  amount  and  quality  of  work  done  will  depend  much 
upon  the  organization  of  the  force.  A  good  foreman  will 
soon  learn  the  good  points  of  his  men  and  distribute  them 
accordingly.  A  gang  of  14  or  16  men  should  be  distributed 
as  follows:  Two  with  jacks;  two  to  tamp  the  ends  of  the 
ties;    four  to  tamp  the  centers,   and   the   remaining   men 


1072  TRACK  WORK. 

equally  divided,  one-half  to  be  employed  in  filling  in  ahead 
of  the  tampers  and  the  other  half  in  dressing  up  the  track 
behind  them.  By  dividing  up  the  men  equally,  placing  one- 
half  the  force  on  each  side  of  the  track,  competition,  both  in 
amount  and  quality  of  work,  naturally  follows.  With  such 
an  organization,  a  foreman  can  effectively  employ  a  force 
within  comparatively  small  limits,  enabling  him  to  give 
thorough  inspection  to  all  work,  and  to  give  directions 
wherever  needed. 

In  raising  track,  both  sides  should  be  lifted  together. 
The  common  custom  of  raising  and  tamping  one  side  of  the 
track  at  a  time  should  not  be  permitted,  as  ties  can  not  be 
given  a  uniform  bearing. 

The  centers  of  track  ties  should  not  be  hard  tamped. 
The  greater  part  of  the  train  load  comes  upon  the  ends  of 
the  ties,  and  if  their  centers  are  hard  tamped  there  is  great 
danger  of  the  ties  being  broken,  especially  if  they  are  sawed 
ties.  The  ties  should  be  hard  tamped  only  18  inches  inside 
the  rails.  This  will  insure  a  firm  bed  and  prevent  all  danger 
of  breaking. 

Uniformity  of  work  is  the  secret  of  a  smooth  track,  and 
the  more  alike  the  men  work,  the  better  will  be  the  results. 

1643.  Yard  Work. — All  yard  tracks  should  be  uni- 
formly surfaced  throughout  their  entire  length.  The  grade 
for  all  yard  tracks  should  be  given  by  the  company's  engin- 
eer, and  should  practically  conform  to  that  of  the  main  line. 
If  possible,  yard  tracks  should  be  level.  Cars  are  then 
much  more  manageable  and  easier  handled.  Where  the 
yard  and  main  tracks  are  of  the  same  level,  the  main  line 
should  be  put  in  perfect  surface  first.  The  adjoining  yard 
track  may  then  be  given  an  equal  height  by  a  level  and 
straight-edge.  In  the  same  way,  any  number  of  side  tracks 
can  be  brought  to  the  level  of  the  main  track.  It  is,  how- 
ever, much  the  better  practice  to  have  all  elevations  given 
with  an  instrument. 

1644.  Gravel  as  a  Destroyer  of  Weeds. — One  of 

the  great  advantages  of  gravel  ballast  is  the  saving  in  the 


TRACK  WORK.  1073 

cost  of  weed  cutting.  Although  ballasting  with  gravel  is  a 
heavy  initial  expense,  the  outlay  ceases  when  the  work  is 
complete.  Weed  cutting,  on  the  other  hand,  is  a  constant 
and  heavy  expense,  and  one  of  the  great  arguments  in  favor 
of  gravel  ballast  is  that  gravel  discourages  the  growth  of 
weeds  and  thereby  saves  to  the  company  a  large  annual  ex- 
pense. A  railroad  company  should  commence  ballasting 
with  gravel  at  the  earliest  possible  moment,  even  though  it 
is  done  in  a  fragmentary  way,  as  every  rail  length  of  gravel 
is  clear  gain. 

1645.  A  Day's  Work.— Two  rail  lengths,  or  GO  feet 
of  finished  track,  ballasted  and  dressed,  per  man,  is  con- 
sidered a  fair  day's  work.  Foremen  should  stop  raising 
track  long  enough  before  quitting  time  to  line  up,  fill  in,  and 
dress  all  the  track  raised  during  the  day.  Track  left  with- 
out the  ties  being  filled  in  and  the  shoulders  properly  dressed 
is  easily  thrown  out  of  line.  A  heavy  shower  falling  upon 
track  which  has  not  been  properly  filled  in  and  dressed  is 
certain  to  do  great  injury.  In  all  cases,  track  should  be 
left  in  a  finished  condition. 


FALL    TRACK    WORK. 

1646.  Importance  of  Fall  Work. — On  Northern 
railroads,  the  prime  object  of  fall  track  work  is  to  prepare 
for  the  ensuing  winter.  One  day's  work  in  the  fall  expended 
in  intelligent  track  work  is  worth  an  entire  week  of  repairs 
in  winter.  The  section  foreman  should  lay  out  his  work 
according  to  the  needs  of  his  section,  and,  as  far  as  possible, 
adhere  to  his  program. 

1647.  Surfacing  and  Lining  Track. — The  most 
important  part  of  the  fall  work  is  the  surfacing  and  lining 
of  track.  In  addition,  the  track  must  be  put  in  perfect 
gauge  and  dressed  down. 

In  dressing  the  track,  give  as  much  strength  to  the 
shoulders  as  the  available  material  will  permit.  With 
drainage  provided  for,  the  heavier  the  shoulder,  the  longer 
the  track  will  hold  its  line  and  withstand  frost. 


1074 


TRACK  WORK. 


1648.     Seeding^  and  Repairing  Embankments. — 

It  is  the  severe  frosts  of  winter,  followed  by  heavy  spring 
and  summer  rains,  which  destroy  embankments.  After  a 
heavy  spring  freshet,  embankments  are  furrowed  with  deep 
gulleys,  though  the  usual  effect  is  the  gradual  wasting  of  the 
slopes.  The  only  protection  against  these  destructive  agents 
is  a  good  sod,  and  foremen  should  be  supplied  with  grass 
seed  of  suitable  variety  to  seed  embankments  whenever  the 
conditions  are  favorable. 

Until  embankments  are  protected  by  grass  they  must  be 
repaired  from  time  to  time.  Narrow  embankments  give 
insufficient  support  to  the  track,  and  sags  are  the  result. 
The  fall  of  the  year  is  the  best  time  to  repair  embankments. 
All  the  material  obtained  from  cleaning  ditches,  widenmg 
cuts,  or  from  any  other  source,  should  be  deposited  upon 
the  embankments  where  there  is  greatest  need  of  repair. 
This  material  the  section  men  can  transport  on  a  push  car, 


Fig.   612. 

which  should  be  fitted  with  sideboards  so  as  to  carry  a  full 
load.  A  section  foreman  can  do  much  towards  keeping  his 
embankments  in  proper  shape,  especially  if  he  be  well  pro- 
vided with  men.  If  there  are  bad  sags  on  his  section,  he 
should  not  attempt  to  take  them  out  until  he  knows  how 
much  material  is  required  for  raising  the  roadbed  to  the 
proper  height.  He  can  determine  the  necessary  amount  of 
filling  by  the  following  approximate  method  (see  Fig.  512). 
Drive  a  stake  at  C  against  the  rail  at  the  middle  point  of 
the  sag  until  its  top  is  on  line  with  the  track  surface  at 
A  and  B.  Measure  the  height  C  D  oi  the  stake  above  the 
rail.  Multiply  one-half  the  distance  A  B  by  the  top  width 
of  the  embankment  and  by  the  height  C  D  oi  the  stake 
above  the  rail;  divide  the  product  by  27.  The  quotient  is 
the  number  of  cubic  yards  of  material  required. 


TRACK  WORK.  1075 

Example. — A  B  is  200  ft.,  C D  \%\  ft.,  and  the  top  of  the  embank- 
ment is  14  ft.  in  width ;  how  many  cubic  yards  of  material  are  necessary 
to  take  out  the  sag  ? 

Solution. — Number  of  cubic  yards  =  -5-  x  14  x  1  -^  37  =  52,  nearly, 
Ans. 

A  push  car  with  sideboards  will  carry  1  cubic  yard  of 
material.  If  the  men  and  material  are  at  hand,  commence 
by  raising  the  sag  near  the  middle,  extending  the  raising  on 
both  sides  until  the  ends  are  reached.  Raise  the  track  at 
the  middle  of  the  sag  about  y^  higher  than  the  total  depth 
of  the  sag,  to  allow  for  shrinkage  of  the  material. 

1649.  General  Repairs. — Carefully  examine  all 
joints,  tightening  loose  nuts  and  renewing  bolts  where  they 
are  broken  or  stripped  of  their  thread.  See  that  proper  pro- 
vision is  made  for  expansion,  and  that  all  ties  are  full  spiked. 
Rotten  ties  left  over  from  the  work  of  the  previous  spring 
should  be  replaced  with  new  ones.  If  new  steel  is  required, 
see  to  it  that  it  is  laid  early  in  the  fall  and  the  track  well 
settled  before  winter  begins. 

Thoroughly  repair  the  right  of  way  and  snow  fences. 
The  winter  season  puts  all  fences  to  the  test,  and  they 
should  be  in  thorough  repair  if  they  are  to  do  service  the 
following  summer. 

1650.  Building  Ne-w  Fence. — Though  the  spring  is 
the  most  favorable  season  of  the  year  for  building  fence,  the 
more  urgent  track  repairs  fully  occupy  the  time  of  every 
section  man.  Consequently,  fence  building  is  deferred 
until  the  late  summer  or  fall.  The  one  disadvantage  to 
building  fence  when  the  season  is  well  advanced  is  the  hard- 
ness of  the  ground,  which  makes  the  digging  of  post  holes 
much  more  laborious  than  in  the  early  spring,  when  the 
ground  is  soft  and  yielding.  There  are,  however,  the  fol- 
lowing advantages  in  favor  of  building  fence  in  the  fall 
season.  Posts  and  lumber  are  usually  much  better  seasoned 
in  the  fall  than  in  the  spring;  streams  are  low,  and  swampy 
places  are  either  entirely  dry  or  at  least  accessible.     It  is 


1076 


TRACK  WORK. 


important  that  posts  should  be  peeled  and  well  seasoned  be- 
fore setting;  and  as  they  are  usually  cut  in  the  winter 
season,  by  delivering  them  at  the  section  house  in  the  win- 
ter or  early  spring,  the  section  men  can  peel  and  pile  them 
on  stormy  days;  they  will  thus  be  thoroughly  seasoned 
when  needed  the  following  fall. 

The  most  effective  fence  js  of  barb  wire  with  one  board  at 
the  top,  as  shown  in  Fig.  513.  Posts  are  spaced  8  feet  between 
centers  and  set  2  feet  6  inches  into  the  ground.  At  intervals 
of  500  feet  on  straight  lines,  and  at  every  angle,  braces 
A  B  should  be  built  into  the  fence.  The  brace  is  mortised 
into  the  post  at  the  top  and  gained  into  the  post  at  the  bot- 
tom. The  wires  are  spaced  as  follows,  beginning  at  the 
bottom  wire,  which  is  9  inches  above  the  ground :    The  first 


Fig.  51S. 


and  second  wires  are  9  inches  apart ;  the  second  and  third, 
10  inches;  the  third  and  fourth,  10  inches  apart,  and  the 
fourth  is  spaced  10  inches  from  tKe  top  board  or  rail,  which 
is  6  inches  in  width.  This  makes  the  total  height  of  the 
fence  4  feet  6  inches,  which  is  a  lawful  fence  in  most  of  the 
States,  and  the  total  length  of  the  posts  7  feet.  In  laying 
out  a  fence,  measure  from  the  center  line  of  the  track,  one- 
half  the  width  of  the  right  of  way,  and  set  a  temporary 
post.  Place  these  posts  from  50  to  80  rods  apart  on  tan- 
gents and  from  50  to  100  feet  apart  on  curves.  Then  stretch 
a  light  wire  between  these  posts,  with  tags  at  intervals  of 
8  feet  for  spacing  and  lining  the  posts.  A  man  then  takes 
a  lining  bar  and  spade  and  plumbs  down  from  each  tag  with 
the  bar,  making  a  mark  with  the  point  of  the  bar.  He  then 
removes  the  sod  from  around  the  hole  made  with  the  bar. 


TRACK  WORK.  1077 

The  hole  marks  the  center  of  a  post  and  guides  the  men 

who   dig  the   post   holes.     The   wire  is  removed  while  the 

holes  are  being  dug,  and  replaced  to  give  line  for  setting  the 

posts.    The  diggers  should  be  provided  with  a  gauge  giving 

the  proper  depth  of  hole.    Those  nailing  on  either  boards  or 

wire  must  be  provided  with  a  gauge  giving  top  of  fence  and 

the  spacing  of  each  strand  of  wire. 

A  handy  gauge  for  spacing  wires  is 

shown  in  Fig.  514.     It  consists  of  a 

foot  piece   of  pine  2  feet  in  length. 

6    inches   in    width,   and    1    inch    in 

thickness.       Another    piece   of   pine 

3  inches  wide  and  4  feet  6  inches  in 

length,  equal  to  the    height   of   the 

fence,  is  nailed  to  the  foot  piece  at 

its   middle,  as  shown   in  the  figure. 

The  spacing  of  each  wire  from  the  ...-^ 


1 

.. 

o 

^ 

?.« 

1  ■  ■ 

ground   is   marked   by  a  notch   cut  ^'°-  ^''*- 

into  the  edge  of  the  upright  piece.  The  foot  piece,  besides 
giving  the  height  from  the  average  surface  of  the  ground, 
helps  to  keep  the  gauge  in  an  upright  position. 

In  building  the  fence  described  above,  judgment  should 
be  used  in  distributing  the  force  if  first-rate  progress  is  to 
be  made.  With  a  force  of  a  dozen  men,  the  following  dis- 
tribution is  recommended :  Two  men  to  lay  out  the  work, 
four  digging  holes,  three  setting  posts,  and  three  nailing  on 
boards  and  stringing  wires. 

A  wire  stretcher  is  necessary  to  first-class  work  and  prog- 
ress, though  good  work  at  stretching  wire  can  be  done 
withi  a  crowbar  if  sufficient  care  and  strength  is  used. 

At  highway  bridges  and  culverts,  the  fence  usually  re- 
turns to  the  ends  of  the  abutments.  The  angles  made  in 
the  fence  by  these  returns  must  be  thoroughly  braced. 
Effective  braces  for  such  returns  are  shown  in  Figs.  515  and 
516. 

In  Fig.  515  the  angle  of  the  return  is  00°,  and  a  brace  in 
each  panel  abutting  on  the  angle  is  sufficient,  but  in  Fig. 
516,  where  the  angle  contains  150°,  an  inside  brace  is  added. 


1078 


TRACK  WORK. 


This  brace  abuts  against  a  short  post  set  in  the  ground  to 
receive  the  thrust  of  the  brace. 

Braces  must  be  placed  at  each  opening,  such  as  farm  and 


Fig.  515. 


Fig.  516. 


road  crossings,  and  at  all  points  where  changes  in  direction 
require  it. 

At  streams  crossed  by  pile  bridges,  it  is  customary  to  make 
a  return  in  the  fence  on  both  sides  of  the  stream,  and  to 
string  the  wires  across  the  stream,  fastening  them  to  the 
piles. 

On  tangents,  and  on  the  outside  of  curves,  place  boards 
and  wire  on  the  farmers'  side  of  the  posts,  but  on  the  inside 
of  curves  place  them  on  the  track  side  of  the  line  of  posts. 


1651.  Material  for  One  Mile  of  Fence.— It  will 
require  661  posts  spaced  8  feet  between  centers  to  build  one 
mile  of  fence.  One  fence  board  16  ft.  long,  6  in.  wide,  and 
1^  in.  thick  contains  10  sq.  ft.  of  lumber,  and  330,  the  num- 
ber of  boards  required  for  1  mile  of  fence,  will  contain 
330  X  10  =  3,300  sq.  ft. 

Barb  wire,  of  average  weight,  weighs  1  lb.  per  rod  of  sin- 
gle wire  or  4  lb.  per  rod  of  finished  fence.  Hence,  for  1 
mile,  or  320  rods,  it  will  require  320  X  4  =  1,2801b.  Adding 
10  lb.  for  splices,  we  have  1,280  +  10  =  1,2901b.,  the  amount 
of  barb  wire  required  for  1  mile  of  fence.  It  will  require 
^  lb.  of  staples  for  1  rod  of  fence,  and  for  1  mile,  or  320 
rods,  it  will  require  320X^=40  lb.,  and  we  have  the 
followin'T 


TRACK  WORK.  10l9 

TABLE   OF   MATERIAL   FOR   1   MILE   OF  FENCE. 


Posts. 

Boards. 

Barb  Wire. 

Staples. 

661 

3,300  sq.  ft. 

1,290  lb. 

40  lb. 

When  barb-wire  fences  were  first  introduced,  the  posts  and 
braces  were  the  only  wood  material  used,  but  they  proved 
very  injurious  to  live  stock,  which,  failing  to  see  the  wire, 
continually  came  in  hurtful  contact  with  the  barbs.  This 
objection  is  removed  by  placing  a  single  board  for  the  top 
rail.  This  board  clearly  marks  the  fence  line,  and,  together 
with  the  barb  wire,  makes  the  most  effective  fence  known. 

1652.  A  Day's  Work  at  Fence  Building.—From 

12  to  14  rods  per  man  is  a  fair  day's  work  at  fence  building, 
though  much  depends  upon  the  hardness  of  the  ground,  the 
quality  of  the  work,  and  the  skill  and  industry  of  the  work- 
men. Fence  building  requires  intelligent  industry.  A 
poorly  built  fence  is  little  better  than  no  fence. 

1653.  Distributing  Emergency  Material. — In  the 

late  fall,  but  before  any  snow  falls,  place  at  each  mile  post, 
and  well  up  from  the  ground,  a  number  of  rails  and  joint 
splices  to  be  used  in  case  of  emergency,  and  known  as 
emergency  material.  Such  supplies  are  available  when 
most  needed,  and  are  constantly  near  at  hand. 

All  track  material  lying  about  the  yard  should  be  collected 
and  piled  well  off  the  ground.  Piles  of  ties  must  be  placed 
far  enough  apart  to  avoid  catching  fire  from  one  another  in 
case  of  fire.  All  loose  spikes,  splices,  bolts,  and  nuts 
should  be  collected  and  placed  under  covef,  and  everything 
about  the  station  made  snug  and  safe  for  the  winter. 


WINTER  TRACK  WORK. 

1654.     General  Repairs. — As  winter  approaches,  the 

entire  section  should  be  gone  over  carefully,  tightening  up 

all  loose  splices,  correcting  defects  in  gauge,  and  closing  up 

joints  which  the  contraction  of  the  rails  has  left  too  open. 


1080  TRACK  WORK. 

The  joints  of  switches  are  most  liable  to  be  open  and  the  rails 
battered.  Close  up  these  joints  and  renew  the  rails  if  neces- 
sary. See  that  switch  joints,  rods,  and  frogs  are  in  proper  or- 
der, and  that  guard-rails  are  properly  spaced  and  well  spiked. 
Keep  all  spikes  driven  home,  clear  the  snow  from  yard 
tracks  and  switches,  flange  out  the  main  track  after  every 
snow  storm,  and  remove  ice  from  the  ditches. 

1655.  Shimming  Track. — There  is  no  work  con- 
nected with  track  repairs  requiring  more  care  and  judgment 
than  shimming.  All  mud-ballasted  tracks  are  bound  to 
heave  from  the  action  of  the  frost,  and  heaving  spoils  the 
surface  of  the  track.  Inequalities  as  small  as  ^  inch  should 
be  corrected  by  shims  placed  beneath  the  rail.  Shims  should 
be  made  of  hard  wood,  slightly  wedge-shaped,  and  driven 
crosswise  under  the  rail.  All  shims  over  ^  inch  in  thick- 
ness should  have  a  hole  bored  in  them  to  receive  the  spike. 
They  are  easiest  made  by  boring  a  hole-  through  the  end  of 
a  straight-grained  plank  and  cutting  off  a  piece  to  the  re- 
quired length,  after  which  the  plank  may  be  split  into  shims 
of  the  required  thickness.  If  the  rail  has  cut  into  the  tie, 
the  edges  of  the  groove  must  be  adzed  smooth  before  pla- 
cing the  shims,  in  order  that  the  rails  may  have  a  solid  bear- 
ing. If  the  track  continues  to  heave,  thin  shims  must  be 
replaced  by  thicker  ones.  Where  a  number  of  ties  side  by 
side  require  shimming,  a  plank  should  be  placed  lengthwise 
under  the  rail  and  spiked  to  the  ties  with  boat  spikes  and 
track  spikes  driven  through  the  plank  to  hold  the  rail. 
Where  shims  exceed  1  inch  in  thickness,  spikes  7  or  8  inches 
in  length  should  be  used. 

For  4-inch  shims  use  1-inch  shims  on  top  of  3-inch  plank, 
and  for  5-inch  shims,  use  5-inch  timber.  Where  shims  ex- 
ceed 1  inch  in  thickness,  old  rail  splices  should  be  set  with 
one  end  against  the  outside  of  the  rail  and  the  other  end 
spiked  to  the  tie  to  serve  as  rail  braces.  These  braces 
should  be  spiked  to  every  second,  third,  or  fourth  tie, 
according  to  the  height  of  the  shim. 

All  high-shimmed  track  should  be  closely  watched,  and 


TRACK  WORK.  1081 

as  the  frost  leaves  the  track  and  the  track  settles,  thinner 
shims  must  be  substituted  for  the  thick  ones.  The  last 
shim  must  not  be  removed  until  the  frost  has  left  the  ground. 
When  the  shimmed  rail  is  higher  than  the  rest  of  the  track 
by  the  thickness  of  the  shim,  you  may  know  that  the  frost 
has  left  the  track.  All  good  shims,  spikes,  and  braces 
should  be  stored  in  the  tool  house,  to  be  in  readiness  when 
needed  the  following  winter. 

1 656.  Heaved  Bridges  and  Culverts. — Pile  bridges 
and  pile  culverts  require  careful  watching  during  the  winter 
season,  and  whenever  they  are  found  to  be  heaved  out  of 
surface  or  line,  the  bridge  carpenters  should  be  promptly 
notified.  Pile  foundations,  when  heaved  by  frost,  unlike 
earth  foundations,  do  not  resume  their  original  position 
after  the  frost  has  left  the  track.  Neither  does  the  frost 
affect  them  equally,  as  one  or  two  piles  in  a  bent  may  be 
heaved  out  of  surface  while  the  others  are  not  stirred.  This 
places  the  track  in  a  dangerous  condition.  To  remedy  the 
evil,  either  the  track  must  be  shimmed  to  the  surface  of  the 
heaved  piles  or  they  must  be  cut  down  to  the  original  sur- 
face. Where  piles  are  driven  in  deep  water,  the  ice  should 
be  cut  away  from  them  whenever  a  thaw  is  imminent,  as  a 
sudden  rise  in  the  water  may  lift  the  body  of  ice,  and  the 
piles,  being  frozen  fast  in  the  ice,  must  rise  also. 


SNOW. 
1657.  Its  Prevalence  and  Effects. — Nearly  all 
roads  in  the  Northern  States  are  obliged  to  contend  with 
snow,  and,  in  the  Northwest  especially,  the  keeping  of  the 
track  clear  of  snow  constitutes  one  of  the  main  items  of  cost 
of  track  maintenance.  Snow  must  be  contended  with  in 
many  forms,  the  most  common  of  which  is  drifted  snow; 
but  it  is  almost  equally  difficult  to  contend  with  it  when  it 
fills  the  flanges  of  the  rails  with  ice,  or  in  melting  and  freez- 
ing it  fills  the  track  ditches  and  flows  across  the  track, 
covering  the  rails  with  ice  and  threatening  derailment  to  the 
first  passing  train. 


1082  TRACK  WORK. 

1 658.  Snow  Keports. — Immediately  after  every  snow 
storm,  the  section  foreman  should  ascertain  the  condition  of 
his  track,  noting  which  cuts  are  clear  and  which  are  blocked, 
and  how  much  snow  is  in  each  cut,  and  the  lengths  of  the 
drifts.  These  facts  he  should  report  immediately  by  tele- 
graph to  the  roadmaster,  in  order  that  preparations  may  be 
made  to  clear  the  track.  If  the  section  is  clear  of  snow,  it 
should  be  so  reported. 

1659.  Preparing  Track  for  Snow  Plow. — After  a 
storm,  as  soon  as  the  condition  of  the  section  has  been  re- 
ported to  the  roadmaster,  the  foreman  .should  take  all  his 
force  and  put  his  section  in  shape  for  the  snow  plow.  In  all 
cuts  where  the  drifts  are  over  two  feet  in  depth,  the  track 
should  be  cleared  of  snow  and  flanged  out  to  where  the  snow 
has  a  depth  of  at  least  18  inches,  leaving  a  clean  face  to  the 
drift.  Both  ends  of  the  cut  should  have  the  same  treatment. 
Snow  is  most  apt  to  cause  derailment  when  it  is  of  slight 
depth  and  hard,  and  so  ground  into  the  flanges  that  the 
engines  mount  the  rail.  By  clearing  the  track  of  snow  at  the 
commencement  and  ends  of  drifts,  this  danger  is  avoided. 

1660.  Clearing  Switches  and  Flanging  Track.— 

As  soon  as  the  track  is  ready  for  the  snow  plow,  the  men 
should  clear  the  switches  of  snow  from  heel  of  switch  to  frog, 
special  care  being  taken  to  clear  the  switch  rails,  rods,  and 
switch  stand.  The  platform,  track,  and  approaches  to  the 
station  should  also  be  promptly  cleared. 

The  section  foreman  should  next  give  his  attention  to 
flanging  out  the  main  track,  beginning  near  the  summits  of 
the  hard  grades,  and  at  all  points  where  the  work  upon  the 
engines  is  most  severe. 

1 661 .  Clearing  Ditclies  and  Culverts. — If  possible, 
keep  the  ditches  and  culverts  clear  of  snow.  If,  in  the  fall,  a 
tall  stake  is  driven  at  both  ends  of  a  culvert  opening,  there 
will  be  no  trouble  in  locating  it  when  the  culvert  is  com- 
pletely covered  with  drifted  snow.  By  keeping  the  ditches 
open,  all  snow  water  can  run  off  instead  of  accumulating 
and  flooding  the  track,  where  it  is  bound  to  freeze,  making 


TRACK  WORK.  1083 

the  track  not  only  hard  to  operate,  but  a  continual  menace  to 
the  safety  of  trains.  The  ditch  for  snow  water  should  be 
fully  6  feet  from  the  rails  to  insure  the  safety  of  the  track. 

1662.  Snow  Fences. — All  railroads  exposed  to  severe 
and  repeated  snow  storms  should  have  some  protection 
against  drifting  snow.  This  protection  is  best  provided  in 
the  form  of  fences.  Their  efficiency  will  depend  upon  their 
strength,  height,  position,  and  distance  from  the  track.  The 
fence  should  be  placed  at  such  a  distance  from  the  track  that, 
when  drifted  full,  the  snow  will  not  reach  within  30  feet  of 
the  track.  To  effect  this,  the  distance  of  the  fence  from  the 
track  should  be  12  feet  for  each  foot  in  height  of  fence. 
When  the  fence  is  placed  too  near  the  track,  the  snow  will  be 
carried  to  the  track  before  the  fence  is  drifted  full ;  if,  on  the 
other  hand,  the  fence  is  placed  too  far  from  the  track,  the 
wind,  after  clearing  the  fence,  will  fall  and  gather  up  all 
the  snow  between  the  foot  of  the  drift  and  the  track,  and 
carry  it  into  the  cut.  Usually  but  one  side  of  the  track  re- 
quires protection  from  snow,  viz.,  that  side  from  which  snow 
storms  most  prevail.  Most  railroads  in  the  snow  belt  of  the 
United  States  run  in  two  general  directions,  viz.,  east  and 
west,  and  as  most  of  the  severe  storms  prevail  from  the  north, 
northwest,  and  northeast,  the  north  side  of  most  tracks  is  the 
only  one  requiring  protection  from  snow.  At  some  excep- 
tional points  on  the  line,  the  topography  of  the  country  may 
cause  complex  currents  of  air  which  may  produce  results  at 
variance  with  general  rules.  At  all  points,  fences  should  be 
built  to  meet  the  existing  conditions.  In  general,  snow  fences 
are  built  parallel  to  the  track.  For  fences  of  ordinary  height, 
the  following  rule  can  be  safely  followed:  Place  the  fence 
75  feet  from  the  nearest  track  rail,  extending  it  parallel  to 
the  track  the  entire  length  of  the  cut.  Change  the  direction 
of  the  fence  at  both  ends  of  the  cut,  gradually  approaching 
the  track  until  the  ends  of  the  fence  are  100  feet  from  the 
ends  of  the  cut  and  50  or  GO  feet  from  the  track. 

If  the  cut  ends  abruptly  at  the  beginning  of  a  high  embank- 
ment, the  turn  in  the  fence  must  be  made  before  the  end  of 


1084  TRACK  WORK. 

the  cut  is  reached,  in  order  to  protect  the  cut  from  head  and 
quartering  winds.  Cuts  which  are  lined  on  the  storm  side 
by  brush  or  heavy  timber  do  not  require  fencing,  as  the  only 
snow  which  reaches  the  track  is  that  which  falls  directly 
upon  it.  The  brushwood  and  timber  prevent  the  blowing  of 
the  snow.  Cuts  made  in  a  side  hill  where  the  ground  slopes 
off  abruptly  into  a  valley  do  not  require  fencing.  But  where 
there  is  a  long  level  or  gently  rolling  stretch  of  ground  on 
the  storm  side  of  the  track,  the  cut  is  liable  to  drift  full  un- 
less properly  fenced.  When  a  fence  becomes  drifted  full,  its 
height  may  be  readily  increased  by  adding  a  wall  of  blocks 
of  snow  taken  from  the  inside  face  of  the  drift.  So  long  as 
the  weather  remains  cold  a  snow  wall  will  serve  the  full 
purpose  of  a  fence. 

A  first-class  snow  fence,  kept  in  perfect  repair,  will  not 
last  above  10  years,  and  it  becomes  a  question  whether  to 
build  a  snow  fence  or  grade  down  the  cut  so  that  it  will  not 
hold  snow.  The  items  of  cost  to  be  considered  are  the  first 
cost  of  the  fence,  the  annual  repairs,  the  interest  on  each 
charge  for  the  time  it  is  to  serve  in  the  fence,  and  if  these 
combined  items  equal  or  exceed  the  cost  of  grading  down 
the  slopes  so  as  to  keep  the  cut  clear  of  snow,  the  grading 
should  be  done. 

1663.  Bucking  Snow. — The  clearing  of  the  track  of 
snow  belongs  to  the  Roadmaster's  Department,  but  it  is 
essentially  track  work  and  at  times  of  vital  importance  to  a 
railroad. 

A  man  should  be  thoroughly  familiar  with  the  best 
methods  of  bucking  snow  before  taking  charge  of  an  outfit 
to  open  up  a  road  for  traffic  after  a  blockade. 

Before  starting  out  on  the  road,  he  should  be  as  thoroughly 
informed  as  possible  as  to  the  condition  of  the  road,  the 
location,  length,  and  depth  of  drifts.  He  should  have  strong, 
live  engines  and  willing  engineers.  The  snow  plow  should 
be  of  the  best  make  and  able  to  throw  snow  out  of  a  10-foot 
cut.  There  should  be  two  engines  in  the  outfit.  The 
second  engine  follows  closely,  with  a  car,  conductor,  train 


TRACK  WORK.  1085 

crew,  and  shoveling  gang.  When  heavy  drifts  are  encoun- 
tered too  deep  for  one  engine  to  successfully  buck,  the 
second  engine  is  coupled  to  the  first,  and  besides  doubling 
the  momentum,  serves  to  pull  out  the  head  engine  and  plow 
in  case  they  are  stalled.  The  pilot  should  be  removed  from 
the  second  engine,  and  the  coupling  made  short  and  very 
strong.  No  car  or  caboose  should  ever  be  placed  between 
the  engines,  as  they  are  likely  to  cause  a  wreck.  When  the 
drifts  are  more  than  10  feet  deep,  the  top  of  the  drift  must 
be  shoveled  out  down  to  that  depth,  and  a  space  made 
wide  enough  that  effective  work  may  be  done  by  the  plow. 

When  the  snow  is  reported  hard,  each  drift  must  first  be 
carefully  examined  and  its  length  and  height  noted.  If  the 
drift  has  not  been  faced  by  section  men  (that  is,  shoveled 
out  from  the  end  of  the  drift  to  where  its  depth  is  from  15 
to  18  inches),  the  gang  of  shovelers  must  do  the  work  before 
a  run  is  made  with  the  plow. 

Unless  the  drifts  are  properly  facedj  the  plow  is  liable  to 
mount  the  rails,  especially  on  curved  track,  and  often  the 
engine  is  derailed  along  with  the  plow.  All  cars  attached 
to  the  helper  engine  shpuld  be  left  behind  while  bucking 
snow.  If  both  engines  are  not  necessary  to  buck  a  drift,  it 
is  better  to-do  the  work  with  one.  The  helper  engine  should 
only  be  used  where  necessary.  If  the  snow  is  not  too  hard, 
a  good,  heavy  engine  will  clear  a  drift  from  3  to  5  feet  deep 
and  from  500  to  800  feet  in  length  at  one  run.  There  is 
comparatively  no  danger  in  bucking  soft,  deep  snow  with  an 
engine  at  top  speed. 

The  engines  with  a  snow-plow  outfit  should  take  fuel  and 
water  to  their  utmost  capacity  at  every  point  reached  where 
a  supply  can  be  obtained.  Unforeseen  delays  and  mishaps 
may  be  encountered,  and  there  must  be  no  risk  of  a  short 
supply  of  fuel  or  water.  When  the  road  is  badly  blockaded, 
the  helper  engine  should  carry  an  extra  carload  of  coal. 
The  water  supply  can  be  readily  replenished  by  shoveling 
snow  into  the  tank. 

Each  engine  in  the  outfit  should  carry  a  piece  of  steam 
hose,  which  can  be  attached  to  the  siphon  cock,  and  reach 


1086  TRACK  WORK. 

from  it  to  the  water  hole  in  the  tender.  When  the  water 
supply  needs  replenishing,  by  shoveling  snow  into  the  tender 
and  turning  on  the  steam,  a  tank  full  of  water  can  be  quickly 
made.  The  steam  hose  can  also  be  used  to  thaw  the  snow 
and  ice  from  the  machinery  and  track  rails. 

In  plowing  snow  the  speed  of  the  engine  should  always  be 
regulated  by  the  length  and  depth  of  the  drifts.  When  the 
drift  is  deep  and  long,  the  engine  should  back  up  far  enough 
to  attain  full  speed  before  striking  the  drift.  An  experienced 
engineer  will  so  regulate  the  speed  of  his  engine  as  to  leave 
but  little  work  for  the  shovelers. 

The  engineer  of  the  plow  engine  should  always  sound  the 
whistle  when  approaching  a  cut,  in  order  that  section  men, 
if  working  there,  may  be  warned  in  time  to  ^et  out  of  the 
cut.  Failure  to  sound  the  whistle  has  been  a  frequent  cause 
of  accident.  When  it  is  necessary  to  buck  a  drift  a  second 
time,  the  engineer  must  sound  the  whistle  and  be  sure  that 
all  hands  are  out  of  the  cut  before  entering  it.  It  is  almost 
impossible  for  men  to  climb  up  out  of  a  snow  cut  when  first 
opened  up. 

When  the  snow  drift  is  of  such  depth  and  length  that  two 
runs  are  likely  to  not  clear  it,  it  is  the  better  policy  to  shovel 
out  from  both  ends  until  it  is  certain  that  two  runs  will  leave 
a  clear  track. 

When  the  snow  is  both  deep  and  very  hard,  the  crust 
should  be  broken  up  and  shoveled  out  before  any  attempt  is 
made  with  the  plow.  Bucking  deep,  hard  snow  with  the 
crust  unbroken  is  very  severe  work  for  a  locomotive,  and  is 
often  attended  with  danger  to  trainmen.  It  is  far  better  to 
insure  safety  even  at  the  price  of  delay.  It  is  not  advisable 
to  start  out  to  clear  a  track  of  snow  during  a  heavy  storm, 
but  everything  should  be  in  readiness  to  start  the  moment 
the  storm  abates. 

The  invention  of  the  rotary  snow  plow  has  practically 
solved  the  snow  problem,  especially  for  clearing  the  track  of 
hard  snow.  Many  roads  which  suffer  little  from  snow  do 
not  yet  possess  rotary  plows,  and  the  old  custom  of  bucking 
snow  is  still  practised  when  occasion  requires  it. 


TRACK  WORK.  1087 

CURVED  TRACK. 

1664.  Difference  in  Lengtti  of  Inner  and  Outer 
Rails  of  a  Curve. — It  is  evident  that  the  radius  of  the 
outer  rail  of  a  curve  is  greater  than  that  of  the  inner  rail, 
and,  consequently,  its  length  is  greater.  This  difference 
may  be  taken  at  1 3V  inches  per  degree  of  curve  per  100  feet, 
for  standard  gauge  track.  The  difference  in  length  between 
the  inner  and  the  outer  rails  of  a  curve  may  be  found  by 
any  of  the  three  following  rules : 

Rule  1. — Multiply  the  degree  of  the  curve  by  the  length 
in  stations  of  100  feet,  and  this  prodiict  by  1^^  inches.  The 
result  will  be  the  difference  in  length  between  the  inner  and 
outer  rails  in  inches. 

Example. — The  degree  of  a  curve  is  4° ;  its  length  520  feet;  what  is 
the  difference  in  length  between  the  inner  and  outer  rails  of  the  curve  ? 

Solution.— 520  feet  =  5.2  stations  of  100  feet  each.  4  X  5.2  =  20.8. 
I5V  in.  =  1.03125  in.     20.8  X  103125  =  21.45  in.  =  1.7875  ft.     Ans. 

Rule  2. — Multiply  the  distance  between  the  center  lines  of 
the  rails  by  the  length  of  the  curve  in  feet  and  divide  the 
product  by  the  radius  of  the  track  curve. 

Example. — A  4°  curve  is  520  feet  in  length ;  the  distance  between 
the  center  lines  of  the  rails  is  4  ft.  10^  in. ;  what  is  the  difference  in 
length  between  the  inner  and  outer  rails  of  the  curve  ? 

Solution. — The  radius  of  a  4°  curve  is  1432.69  ft.     (See  table  of 

Radii  and  Deflections.)     lOi  in.  reduced  to  the  decimal  of  a  foot  is 

„^„  ,      4.875  X  520      ,  ^^  . 
.87o  ft.       -  ,.^cx  nr.     =  1-  "  ft.     Ans. 
1,432.69 

Rule  3. — Multiply  the  excess  for  a  whole  circumference  by 

the  total  number  of  degrees   in  the  curve,  and  divide  the 

product  by  S60.      The  excess  of  a  whole  circumference,   no 

matter  what  the  degree  of  curve,  is  equal  to  twice  the  distance 

between  rail  centers  multiplied  by  3.  II^IQ. 

Example. — A  4°  curve  is  520  feet  in  length ;  the  distance  from  center 
to  center  of  the  rails  is  4  ft.  lOi  in. ;  what  is  the  difference  in  length 
between  the  inner  and  outer  rails  of  the  curve  ? 

Solution. — The  distance  between  rail  centers  is  4.875  ft.  4  875  x 
2x3.1416  =  30.6306  ft.  A  4"  curve  for  520  ft.  contains  20.8°.  30.6306  X 
20.8-^-360=  1.77  ft.    Ans. 


1088  TRACK  WORK. 

For  light  curves  laid  to  exact  gauge,  the  first  rule  is  the 
simpler  one,  but  for  short  curves  where  the  gauge  is  widened 
use  either  the  second  or  the  third  method. 

These  rules  should  be  applied  in  determining  the  number 
of  short  rails  for  curves,  when  loading  material  at  the  sup- 
ply yard  for  forwarding  to  the  track  layers.  As  previously 
stated,  a  safe  rule  is  one  29^-foot  rail  per  100  feet  for  each 
6  degrees  of  curvature.  In  laying  track  with  either  even 
or  broken  joints,  the  required  number  of  short  rails  must  be 
laid  in  proper  order  if  a  first-class  job  is  to  be  expected.. 

1665.  Curving  Rails. — When  laying  track  on  curves, 
in  order  to  have  a  smooth  line,  the  rails  themselves  must 
conform  to  the  curve  of  the  center  line.  To  accomplish 
this  the  rails  must  be  curved.  The  curving  should  be  done 
with  a  rail  bender  (see  Fig.  495)  or  with  a  lever,  as  shown  in 
Fig.  497.     The  rail  bender  is  preferable. 

To  guide  those  in  charge  of  this  work,  a  table  of  middle 
and  quarter  ordinates  for  a  30-foot  rail  for  all  degrees  of 
curve  should  be  prepared. 

The  accompanying  table  of  middle  ordinates  for  curving 
rails  is  calculated  by  using  the  formula 

in  =  ^,  (112.) 

in  which  in  is  the  middle  ordinate ;  c,  the  chord,  assumed  to 
be  of  the  same  length  as  the  rail,  and  R,  the  radius  of  the 
curve. 

Example. — What  is  the  middle  ordinate  m  of  a  30-foot  rail  for  an 
8°  curve  ? 

Solution. — The  radius  of  an  8°  curve  is  716.78  ft. 
Applying  the  formula,  we  have 

^  =  83r7T6?78=  5773424  =  ^■'^'  ^'-  =  '^  '"•  ^"^^ 
The  results  obtained  from  this  formula  are  not  theoreti- 
cally correct,  yet  the  error  is  so  small  that  it  may  be  ignored 
in  practical  work.  With  a  table  of  radii  such  as  is  given  in 
the  table  of  Radii  and  Chord  and  Tangent  Deflections,  a 
table  of  ordinates  may  be  readily  calculated  by  substituting 
the  known  values  in  formula  112. 


TRACK  WORK. 
TABLE   32. 


1089 


MIDDJLB   ORDINATES  FOR   CURVING   RAILS. 


Lengths 

of  Rails. 

Degree  of 

Curve. 

30  Ft. 

28  Ft. 

26  Ft. 

24  Ft. 

23  Ft. 

20  Ft. 

In. 

In. 

In. 

In. 

In. 

In. 

1 

oi 

OA 

OtV 

OtV 

Of 

Of 

2 

Oi 

OtV 

Of 

OtV 

Oi 

OtV 

3 

OH 

Of 

OA 

OiV 

Of 

OiV 

4 

OH 

OH 

OH 

Of 

Oi 

OiV 

5 

h\ 

ItV 

Oi 

Of 

Of 

OtV 

6 

ItV 

U 

iiV 

0| 

Of 

Of 

7 

If 

1  rV 

u 

ItV 

Of 

Of 

8 

li 

If 

lA 

ItV 

1 

o|  • 

9 

2i 

u 

If 

If 

If 

OH 

10 

2f 

3tV 

If 

U 

li 

lA 

11 

2f 

n 

HI 

iH 

If 

If 

12 

m 

2i 

2i 

iH 

ItV 

U 

13 

3iV 

2H 

2tV 

iH 

If 

If 

14 

3A 

n 

2i 

n 

If 

U 

15 

3^ 

3tV 

2H 

2i 

IH 

iiV 

16 

3f 

3i 

m 

2f 

2iV 

IH 

17 

4 

3i 

3 

9  9 

2iV 

If 

18 

4t\ 

3H 

3A 

2H 

2J, 
''T¥ 

11 

19 

4tV 

3J 

3f 

n 

9  ' 

2 

20 

4H 

4i 

3tV 

3 

2tV 

n 

In  curving  rails,  the  ordinate  is  measured  by  stretching  a 
cord  from  end  to  end  of  the  rail  against  the  gauge  side,  as 
shown  in  Fig.  517.  Suppose  the  rail  .^  .5  is  30  feet  in  length, 
and  the  curve  8°.  Then,  by  the  previous  problem,  the  mid- 
dle ordinate  at  a  should  be  IJ  inches.  To  insure  a  uniform 
curve  to  the  rails,  the  ordinates  at  the  quarters  d  and  d' 
should  be  tested.     In  all  cases  the  quarter  ordinates  should 


1090 


TRACK  WORK. 


be  three-quarters  of  the  middle  ordinate.  In  Fig.  517,  if 
the  rail  has  been  properly  curved,  the  quarter  ordinates  at 
b  and  b'  will  be  f  X  l|in.  =  l^f,  say  If  in. 

With  practice,  a  man  having  a  good  eye  and  good  judg- 
ment will  soon  find  his  eye  measurements  closely  checking 
his  table  measurements.  When  a  quantity  of  rails  are  to  be 
curved  for  curves  of  different  degrees,  it  is  a  good  plan  to 


mark  the  degree  of  the  curve  of  each  rail  in  white  paint  on 
the  web  of  the  rail  on  the  concave  side.  There  should  be 
ample  force  to  handle  the  rails  with  dispatch,  else  much  time 
will  be  wasted.  The  use  of  sledges  in* curving  rails  should 
under  no  circumstances  be  allowed.  There  is  great  danger 
of  fracture,  and  often  a  flaw  is  caused  which  at  the  time  is 
not  perceptible,  but  which  may,  under  the  stresses  caused 
by  frost  and  heavy  trains  at  high  speed,  result  in  a  broken 
rail,  with  serious  consequences. 

In  track  work  it  is  often  necessary  to  ascertain  the  degree 
of  a  curve,  though  no  transit  is  available  for  measuring  it. 
The  following  table  contains  the  middle  ordinates  of  a  one 
degree  curve  for  chords  of  various  lengths: 

TABLE   33. 


Length  of  Chord 

Middle  Ordinate 

in  Feet. 

of  a  V  Curve. 

20  ft. 

\  in. 

30  ft. 

iin. 

44  ft. 

i  in. 

50  ft. 

fin. 

62  ft. 

1    in. 

100  ft. 

2tin. 

120  ft. 

3f  in. 

TRACK  WORK.  1091 

The  lengths  of  the  chords  are  varied  so  that  a  longer  or 
shorter  chord  may  be  used,  according  as  the  curve  is  regular 
or  not. 

The  table  is  applied  as  follows:  Suppose  the  middle  ordi- 
nate of  a  44-foot  chord  is  3  inches.  We  find  in  the  table 
that  the  niiddle  ordinate  of  a  44-foot  chord  of  a  one-degree 
curve  is  ^  inch.  Hence,  the  degree  of  the  given  curve  is 
equal  to  the  quotient  of  3  -=-  ^  =  6°  curve. 

Additional  examples  are  given  as  follows: 

1.  The  middle  ordinate  of  a  100-foot  chord  is  14f  inches; 
what  is  the  degree  of  the  curve  ?  Ans.   5.G°,  nearly. 

The  degree  of  the  curve  is  probably  5°  30'. 

2.  The  middle  ordinate  of  a  50-foot  chord  is  5^  inches; 
what  is  the  degree  of  the  curve  ?  Ans.   8.4°. 

The  degree  of  the  curve  is  probably  8°  30'. 

3.  Calculate  by  rule  1  the  difference  in  lengths  between 
the  inner  and  the  outer  rails  of  a  7°  curve  475  feet  in 
length.  Ans.   34.29  in.  =2. 857  ft. 

4.  Solve  Example  3  by  rule  2.  Ans.  2.827  ft. 

1666.  Springing  Rails  into  Curve. — Rails  should 
never  be  sprung  and  spiked  to  a  curve;  the  elastic  force  of 
the  steel  is  constantly  acting,  and  is  sure  to  force  the  track 
out  of  line.  Each  passing  train,  through  its  centrifugal 
force,  aids  the  rails  to  regain  their  original  form.  The  re- 
sult is  that  in  a  short  time  the  curve,  especially  it  a  sharp 
one,  will  show  an  angle  at  each  joint.  The  effect  at  these 
angles  is  to  cause  a  sudden  lurch  of  the  car  at  each  joint, 
causing  not  only  discomfort  to  passengers,  but  serious  and 
constant  wear  and  strain  upon  the  roiling  stock. 

1667.  Widening  Gauge  of  Curves. — In  passing 
over  curved  track,  the  car  wheels  bind  hard  against  the  out- 
side rail  at  the  curve.  The  reason  for  this  is  that  the  differ- 
ence between  the  gauge  of  the  track  and  the  gauge  of  the 
wheels  is  taken  up  by  the  wheel  base,  which  forms  a  chord 
to  the  curve  of  the  track,  instead  of  being  parallel  to  the 
rails,  as  is  the  case  on  a  straight  line.     To  lessen  this  friction, 


1092  TRACK  WORK. 

the  gauge  is  usually  widened  on  curves  to  the  amount 
of  y^^  inch  per  degree,  but  never  to  exceed  1  inch  on 
any  curve.  The  increase  in  gauge  is  usually  made  in 
quarter-inches,  that  being  the  amount  allowed  for  4  degrees. 
The  necessity  for  widening  the  gauge  on  sharp  curves  is 
still  more  apparent  when  we  consider  that  provision  must 
be  made  to  accommodate  cars  of  both  standard  gauge  (4 
feet  8^  inches)  and  for  those  of  4  feet  9  inches  gauge,  com- 
mon to  Southern  roads. 

When  the  gauge  is  not  widened,  a  wide-gauged  car  is 
liable  to  mount  the  rail,  especially  if  the  flanges  of  the 
wheels  are  badly  worn  and  sharp.  The  effect  of  all  curva- 
ture is  to  increase  the  train  resistance,  and  on  sharp  curves, 
this  resistance,  due  to  friction,  becomes  so  great  as  to 
largely  reduce  the  train  load.  All  train  loads  are  limited 
by  the  maximum  resistance  which  they  must  overcome. 
This  maximum  resistance  may  be  concentrated  upon  a 
single  curve,  and  it  is  at  once  apparent  that  a  railroad  com- 
pany might  well  incur  heavy  expense  in  reducing  this  curv- 
ature, if  by  so  doing  they  could  add  one  extra  car  to  each 
train  load.  Another  charge  against  curvature  is  the  loss  of 
time  to  passenger  trains  which  can  not  run  over  sharp 
curves,  except  at  reduced  speed.  All  curves  exceeding  eight 
degrees,  besides  their  resistance  to  trains,  cause  a  direct 
loss  of  time  to  all  fast  passenger  trains. 

1668.  Guard  Rails  on  Short  Curves. — On  straight 
track,  laid  to  exact  gauge,  the  guard  rail  is  spaced  1|^  inches 
from  the  gauge  rail;  but  when  the  gauge  is  widened,  as  on 
sharp  curves,  the  amount  of  the  increase  in  gauge  must 
be  added  to  the  space  between  the  gauge  and  the  guard 
rail, 

1 669.  LiniuK  Curves. — A  common  habit  of  trackmen 
when  lining  curves  is  to  throw  the  curve  outwards  to  line. 
The  effect  of  this,  in  time,  is  to  reduce  the  degree  of  curva- 
ture at  the  ends  of  the  curve  and  sharpen  it  at  the  cen- 
ter, besides  crowding  the  roadway  on  the  outside  of  the 
curve. 


TRACK  WORK.  1093 

A  safe  rule  is  to  always  throw  the  track  inzvards^  i.  e. ,  tow- 
ards the  center  of  the  curve.  It  is  at  once  apparent  that 
the  effect  of  the  cen- 
trifugal force  of  the 
train  in  passing  over 
a  curve  is  to  throw 
the  track  outwards, 
and  in  lining  curves, 
the  track  should  be 
thrown  inwards,  if 
for  no  other  purpose 
than  to  (Overcome  this 
effect  of  the  trains. 
The  effect  of  throw- 
ing the  track  out- 
wards when  lining  a 
curve  is  shown  in 
Fig.     518,    in    which  fig.sis. 

ABC  represents  the  true  line  of  the  curve  and  A  E  C  the 
position  of  the  tracks  due  to  improper  lining. 

When  track  is  first  laid,  there  should  be  a  track  center 
stake  driven  at  every  50  feet  and  carefully  centered  with  a 
tack.  Before  and  after  ballasting,  the  track  should  be  care- 
fully lined  to  the  center  stakes,  and  if  the  rails  have  been 
properly  curved  the  track  will  hold  its  line,  with  occasional 
retouching,  for  years. 

In  the  case  of  a  badly  lined  curve,  select  a  piece  of  track 
60  feet  in  length,  which  appears  to  be  in  good  line.  There 
are  few  curves,  however  badly  out  of  line,  but  will  show  at 
least  60  feet  of  good  line.  At  each  end  of  the  60  feet  of 
good  track  set  an  accurate  center  stake,  and  one  in  the  cen- 
ter of  the  track  midway  between  them.  In  Fig.  519,  A 
and  B  represent  the  center  stakes  60  feet  apart,  and  C 
the  stake  midway  between  them.  Stretch  a  cord  from  A 
to  B,  and  measure  the  distance  from  Z,  its  middle  point, 
to  C.  The  distance  C  L\s  the  middle  ordinate  of  a  60-foot 
chord.  Next,  mark  the  middle  point  L  of  the  chord,  and 
move  the  end  A  of  the  chord  to  C.     Measure  from  B  the 


1094  TRACK  WORK. 

distance  B  M—  C  L,  and  carry  the  measuring  cord  forwards, 
stretching  it  taut,  and  in  the  line  C  M,  as  determined  by  the 
offset  B  M.  The  forward  end  D  of  the  cord  will  mark  the 
spot  for  another  track  center.  Then,  move  ahead  as  before, 
measuring  another  offset  and  stretching  the  cord  to  locate 
another  center  stake  at  E.  In  this  way  a  perfect  curve  may 
be  run  in  without  the  use  of  an  instrument.  It  is  better 
policy  to  set  the  track  centers  in  line  with  the  faces  of  the 
stakes  for  line  rather  than  the  tack  centers,  as  the  cord  is 
sure  to  line  properly  to  the  faces  of  the  stakes,  but  in  order 

E 


Pig.  519. 


to  line  their  centers  they  must  be  practically  of  the  same 
height,  which  is  sometimes  difficult  to  obtain,  especially  if 
the  ballast  contains  stone. 

Having  set  all  the  track  centers,  select  a  track  gauge 
which  is  square  and  true,  and  mark  a  point  midway  between 
the  gauge  lines.  Then,  place  the  gauge  on  the  track  close 
to  the  track  center,  and  direct  the  men  to  move  the  track 
until  the  middle  point  of  the  track  gauge  coincides  with  the 
track  center.  Line  up  the  track  at  each  track  center  until 
the  entire  curve  has  been  moved  to  line;  then,  repeat  the 
operation,  giving  the  final  touches,  as  a  second  lining  should 
be  sufficient. 

1 670.  Elevation  of  Curves. — To  counteract  the  cen- 
trifugal force  which  is  developed  when  a  car  passes  around 
a  curve,  the  outer  rail  is  elevated.  The  amount  of  elevation 
will  depend  upon  the  radius  of  the  curve  and  the  speed  at 


TRACK  WORK.  1095 

which  trains  are  to  be  run.  There  is,  however,  a  limit 
in  track  elevation,  as  there  is  a  limit  in  widening  gauge, 
beyond  which  it  is  not  safe  to  pass. 

When  we  consider  that  the  centrifugal  force  of  a  car  in- 
creases as  the  degree  of  curvature,  and  as  the  square  of  the 
speedy  we  readily  see  how  a  slight  decrease  in  speed  will 
equalize  a  great  increase  in  curvature. 

To  illustrate:  A  car  passing  around  an  8-degree  curve 
will  have  double  the  centrifugal  force  of  a  car  passing  around 
a  4  degree  curve  at  the  same  speed.  But  to  neutralize  the 
eflfect  of  sharpening  the  curve  from  4  to  8  degrees,  it  is  not 
necessary  to  halve  the  speed,  but  only  to  reduce  it  in  an  inverse 
proportion  to  the  square  root  of  the  degrees  of  curvature. 
Thus,  if  a  speed  of  60  miles  per  hour  is  admissible  on  a  4-de- 
gree  curve,  the  speed  on  an  8-degree  curve  is  obtained  by  the 
proportion  60  :  a' =  |/8^  :  4/4,  or  .r  =  42.43  miles  per  hour. 
If  we  again  double  the  degree  of  the  curve  to  16  degrees, 
we  only  reduce  the  admissible  speed  of  equal  safety  to  30 
miles  per  hour.  Hence,  it  will  be  seen  that  the  centrifugal 
force  developed  by  an  increase  in  speed  is  not  proportional 
to  the  centrifugal  force  developed  by  an  increase  in  curva- 
ture. In  consequence  of  this  varying  relation  between  curva- 
ture and  speed,  no  fixed  rule  can  be  followed  for  elevating 
the  outer  rail  of  curves. 

It  is  a  safe  rule  to  elevate  all  curves  to  suit  the  highest 
speed  of  trains  passing  over  that  part  of  the  track.  Ordi- 
narily freight  trains  require  the  same  track  elevation  as  pas- 
senger trains.  All  railroad  men  know  that  freight  trains 
repeatedly  run  at  passenger  train  speed.  The  aim  of  every 
freight  train  conductor  is  to  "make  time, "  and  he  makes 
it  whenever  the  grades  and  train  loads  permit. 

On  rolling  grades  it  is  often  necessary  to  run  down  a  grade 
at  top  speed  in  order  to  acquire  sufficient  momentum  to 
carry  the  train  to  the  summit  of  the  following  grade.  Every 
day  fast  running  is  necessary  in  order  to  make  up  for  time 
lost  through  unavoidable  delays;  hence,  if  a  curved  track  is 
elevated  to  meet  the  requirements  of  passenger  trains,  freight 
trains  will  be  equally  well  served.     All  curves,  when  possible, 


1096  TRACK  WORK. 

should  have  an  elevated  approach  on  the  straight  main 
track,  of  such  length  that  trains  may  pass  on  and  off  the 
curve  without  any  sudden  or  disagreeable  lurch.  The 
length  of  the  approach  should  be  in  proportion  to  the 
elevation  of  the  curve  and  not  to  its  degree. 

A  good  rule  for  curve  approaches  is  the  following:  For 
each  half-inch  or  fraction  thereof  of  curve  elevation,  add 
30  feet  or  1  rail  length  to  the  approach ;  that  is,  if  a  curve 
has  an  elevation  of  2  inches,  the  approach  will  have  as  many 
rail  lengths  as  ^  is  contained  in  2,  which  is  4  times.  The 
approach  will,  therefore,  have  a  length  of  4  rails  of  30  feet 
each,  or  120  feet. 

The  following  formula  by  Searles,  viz. , 

c  =  1.5S7V,  (113.) 

gives  the  length  of  the  chord  c,  whose  middle  ordinate  is 
equal  to  the  proper  elevation  of  the  outer  rail  of  the  curve 
for  any  velocity  V  in  miles  per  hour. 

Example. — The  curve  is  8°,  and  the  velocity  40  miles  pei  hour ;  what 
is  the  proper  elevation  for  the  outer  rail  of  the  curve  ? 

Solution. — Substituting  the  given  values  in  formula  113, 
^  =  1.587  V, 
we  have  c  —  1.587  X  40  =  63.48  feet,  the  length  of  the  required  chord. 
To  find  the  middle  ordinate  of  this  chord,  we  apply  formula  112. 
We  have  just    found  c  —  63.48   feet,  and  R  —  the  radius  of  an  8° 
curve  =  716.78  feet. 

Substituting  these  values  of  c  and  R  in  the  above  formula,  we  have 
63.48*  4,029.7 

^  =  83<-7T6:78  =  57734:2  =  -'^^'-"^^'"^y  =  ^^'"-      ^"^- 

This  result  is  too  great.  The  best  authorities  on  this 
subject  place  the  maximum  elevation  at  \  the  gauge,  or 
about  8  inches  for  standard  gauge  of  4  feet  8^  inches.  The 
gauge  on  a  10°  curve  elevated  for  a  speed  of  40  miles  an 
hour  should  be  widened  to  4  feet  ^d\  inches. 

The  following  table  for  elevation  of  curves  is  a  com- 
promise between  the  extremes  recommended  by  different 
engineers.  It  is  a  striking  fact  that  experienced  trackmen 
never  elevate  track  above  6  inches,  and  many  of  them 
place  the  limit  at  5  inches: 


TRACK  WORK. 
TABLE  34. 


1097 


Degree 
of  Curve. 

Length  of 
Approach. 

Elevation. 

Width  of 
Gauge. 

Speed 

of  Trains. 

1 

60  ft. 

1     in. 

4  ft.  8|  in. 

60  m] 

.  per  hr. 

2 

120  ft. 

2    in. 

4  ft.  8^  in. 

60  mi 

.  per  hr. 

3 

150  ft. 

2^  in. 

4  ft.  8f  in. 

60  mi 

.  per  hr. 

4 

180  ft. 

2f  in. 

4  ft.  Si  in. 

55  mi 

.  per  hr. 

5 

180  ft. 

3    in. 

4  ft.  8|  in. 

50  mi 

.  per  hr. 

6 

210  ft. 

Biin. 

4  ft.  8|  in. 

45  mi 

.  per  hr. 

7 

210  ft. 

3iin. 

4  ft.  9    in. 

40  mi 

.  per  hr. 

8 

240  ft. 

3iin. 

4  ft.  9    in. 

35  mi 

.  per  hr. 

9 

240  ft. 

4    in. 

4  ft.  9    in. 

30  m 

.  per  hr. 

10 

270  ft. 

4iin. 

4  ft.  9    in. 

25  m 

.  per  hr. 

11 

270  ft. 

4iin. 

4  ft.  9i  in. 

20  m 

.  per  hr. 

12 

270  ft. 

4f  in. 

4  ft.  9i  in. 

15  m 

.  per  hr. 

13 

240  ft. 

4i  in. 

4  ft.  9i  in. 

10  m 

.  per  hr. 

14 

240  ft. 

4iin. 

4- ft.  9iin. 

10  m 

1.  per  hr. 

15 

240  ft. 

4    in. 

4  ft.  9^  in. 

10  m 

I.  per  hr. 

16 

240  ft. 

4    in. 

4  ft.  9^  in. 

10  m 

.  per  hr. 

Many  persons  overrate  the  objections  to  sharp  curves, 
especially  where  the  grades  are  low.  Their  great  objection 
is  not  in  their  being  an  obstacle  to  high  speed,  but  in  their 
great  resistance  to  traction.  Freight  trains,  which  are 
usually  heavily  loaded,  are  much  more  impeded  by  sharp 
curves  than  passenger  trains,  which  are  generally  lighter 
and  made  up  of  cars  which  more  readily  adjust  themselves 
to  irregularities  in  line  and  surface. 

No  curve  exceeding  10  degrees  should  be  placed  in  the 
main  line  of  any  railroad.  The  additional  cost  of  operating 
and  maintaining  a  sharper  curve  would  pay  for  tne  addi- 
tional outlay  necessary  to  bring  the  degree  within  the  10- 
degree  standard.  Many  roads  place  the  maximum  curve  at 
6  degrees,  and  though  beyond  the  reach  of  many  roads,  it  is 
a  safe  standard. 


1098  TRACK  WORK. 

Besides  the  loss  of  time  necessitated  by  running  slowly  on 
short  curves,  there  is  a  much  greater  loss  due  to  the  wear 
and  tear  on  rolling  stock  and  upon  the  rails  themselves. 
The  friction  of  the  wheel  flanges  against  the  rails  rapidly 
wears  them  out,  and  the  continual  lurching  and  rolling  of 
the  cars  detract  greatly  from  the  comfort  of  passengers. 

Most  of  the  trunk  lines  in  the  United  States  have  been 
greatly  improved  since  their  first  construction,  especially  in 
their  alinement,  some  of  them  being  practically  rebuilt. 
The  Pennsylvania  R.  R.  between  Philadelphia  and  Harris- 
burg  is  a  striking  instance  of  the  great  improvement,  both 
in  alinement  and  grade,  of  a  line  originally  cheaply  and 
poorly  built.  Many  of  the  original  curves  have  been  re- 
moved, and  all  of  them  lightened.  In  many  places  the 
original  line  has  been  entirely  abandoned,  and  a  new  and 
better  one  adopted.  This  road  is,  however,  an  exceptional 
case,  as  few  lines  in  the  world  could  afford  to  make  slight 
changes  involving  so  great  cost. 

1671.  The  Elevation   of  Turnout   Curves. — The 

speed  of  all  trains  in  passing  over  turnout  curves  and  cross- 
overs is  greatly  reduced,  so  that  an  elevation  of  ^  inch 
per  degree  is  amply  sufficient  for  all  curves  under  16  degrees. 
On  curves  exceeding  16  degrees,  the  elevation  may  be  held 
at  4  inches  until  20  degrees  is  reached,  and  on  curves  ex- 
ceeding 20  degrees,  -^  of  an  inch  of  elevation  per  degree 
may  be  allowed  until  the  total  elevation  amounts  to  5  inches, 
which  is  sufficient  for  the  shortest  curves. 

1672.  Curve  Approaches  liet^'een  Reverse 
Curves. — If  possible,  there  should  be  a  level  piece  of  track, 
at  least  60  feet  in  length,  between  reverse  curves,  besides 
the  elevated  approaches  to  the  curves.  When  the  whole  of 
the  intermediate  tangent  is  required  in  making  the  elevated 
approaches  to  the  curves,  commence  at  the  middle  of  the 
intermediate  tangent,  if  both  curves  are  of  the  same  degree. 
If,  however,  they  are  of  different  degrees,  make  the  ap- 
proach to  each  curve  in  proportion  to  its  degree.  In  ele- 
vating the  approaches  to  the  curves,  give  to  the  first  rail 


TRACK  WORK. 


1099 


length  an  elevation  of  ^  inch,  after  which  give  ^  inch  addi- 
tional elevation  per  rail  length,  or,  if  necessary,  1  inch 
additional  elevation,  so  as  to  make  the  total  elevation  of  the 
approach  equal  to  the  elevation  of  the  outer  rail  of  the 
curve. 

When  a  curve  is  compounded,  commence  to  increase  or 
decrease  the  elevation  far  enough  back  from  the  point  of 
compound  curvature  to  give  to  the  second  branch  of  the 
compound  curve  the  elevation  which  it  requires.  This  in- 
crease or  decrease  in  elevation  is  made  at  the  rate  of  ^  inch 
per  rail  length,  precisely  as  in  elevating  the  approach  to  a 
regular  curve.  When  the  changes  in  a  compound  curve  are 
frequent  and  abrupt,  it  is  best  to  elevate  the  outer  rail  for 
the  highest  degree  of  the  curve  and  carry  this  elevation 
uniformly  throughout  the  curve. 

1673.     Putting  the  Elevation  in  Curves. — If  the 

track  is  in  good  surface,  first  catch  up  all  the  low  joints  on 
the  inner  rail  of  the  curve.  The  elevation  of  the  outer  rail 
is  determined  by  means  of  the  track  level  shown  in  Fig. 
520.     For  leveling  track,  the  edge  a  boi  the  track  level  is 


Fig.  520. 

placed  upon  the  rails,  and  when  perfectly  level  the  bubble  c 
of  the  spirit  level  will  rest  in  the  middle  of  the  tube.  The 
steps  d,  e,  etc.,  of  the  track  level  are  made  1  inch  in  height, 
so  that  when  the  step  ^-is  placed  on  the  outer  rail  of  a  curve 
and  the  rail  raised  until  the  bubble  of  the  spirit  level  rests 
in  the  middle  of  the  tube,  the  outer  rail  has  an  elevation  of 
1  inch.  Similarly,  the  step  e,  when  brought  to  a  level, 
would  indicate  a  track  elevation  of  2  inches,  etc. 

Having  determined  the  amount  of  elevation  required  for 
the  curve,  the  outer  rail  is  raised  with  the  track  jack  and  the 
ballast  thoroughly  tamped  under  the  ties.     The  elevation 


1100  TRACK  WORK. 

should  be  about  ^  inch  in  excess  of  that  required,  in  order 
that  provision  may  be  made  for  settlement. 

In  dressing  the  track  after  the  elevation  has  been  made, 
make  the  crown  of  the  ballast  at  not  more  than  one-third 
of  the  width  of  the  gauge  from  the  outer  rail,  in  order  to 
secure  drainage.  The  raising  of  the  outer  rail  reduces  the 
outer  slope  and  increases  the  inner  slope  of  the  ballast.  If 
the  curve  is  sharp,  the  ballast  on  the  outer  half  of  the  track 
is  practically  level  and  holds  water,  instead  of  shedding  it. 
By  crowning  the  ballast  as  directed,  thorough  drainage  is  in- 
sured. 

1674.  The  Effects  of  Curved  Track  upon  Loco- 
motive and  Car  Wheels. — The  effect  of  all  curved  track, 
however  easy  the  curve,  is  to  wear  the  flanges  and  treads  of 
car  wheels.  This  effect  is  due  to  the  centrifugal  force  which 
forces  the  flanges  of  the  wheels  against  the  head  of  the  out- 
side rail  of  the  curve. 

The  elevation  of  the  outer  rail,  the  widening  of  the  gauge, 
and  the  coning  of  the  car  wheels,  all  combine  to  reduce  this 
friction  and  consequent  wear. 

Where  the  elevation  is  insufficient,  the  friction  increases, 
and  if  the  gauge  is  the  same  as  on  straight  track,  there  is 
great  danger  of  the  wheels  mounting  the  rails,  especially  if 
the  flanges  are  badly  worn.  The  conclusion  from  many 
years  of  experiment  and  close  observation  is  that  the  wear 
of  rails  on  curved  track  is  largely  due  to  the  driving  wheels 
of  the  engine.  When  the  tires  become  worn,  the  wear  of 
the  rails  rapidly  increases,  and  hence  the  importance  of 
careful  and  repeated  inspection  of  the  driving  wheels.  As 
soon  as  they  show  considerable  wear,  the  tires  should  be 
turned  off  to  true  lines.  Besides  preventing  unnecessary 
wear  of  rails,  this  greatly  increases  the  tractive  power  of 
the  engine.  When  the  treads  of  car  wheels  become  badly 
worn,  especially  at  the  flanges,  there  is  bound  to  be  more  or 
less  slipping  of  the  wheels.  For  the  outer  rail,  being  the 
circumference  of  a  greater  circle,  should  require  a  wheel  of 
greater  diameter  than  the  inner  wheel,  if  both  are  to  make 


TRACK  WORK. 


1101 


the  same  number  of  revolutions.  This  increased  diameter  is 
given  by  the  coning  of  the  wheels,  shown  in  Fig.  521,  in 
which  the  rail  a  is  on  the  outside  of  the  curve.  An  inspec- 
tion of  the  figure  will  show  that  the  cone-shaped  tread  of  the 
wheel  b  gives  a  greater  diameter  to  the  wheel  at  c  d  than  at 
e  f.  In  passing  around  the  curve,  the  flange  of  the  wheel  b 
is  forced  against  the  rail  a,  while  the  flange  of  the  wheel  Ji 
recedes  from  the  rail  g.  This  increases  the  diameter  of  the 
wheel  b,  while  decreasing  that  of  the  wheel  //,  and  so  the  ex- 


Fig.  521. 

cess  in  length  of  the  outer  rail  of  the  curve  is  at  least  par- 
tially covered. 

Careful  experiment  proves  that  under  the  most  favoring 
conditions  some  slipping  of  the  wheels  is  bound  to  occur. 
The  friction  between  wheels  and  rails  rapidly  increases  as  the 
rails  become  worn,  and,  as  soon  as  the  head  of  the  outer  rail 
of  a  curve  becomes  badly  worn,  the  outer  rail  should  be 
taken  up  and  placed  on  the  inside  of  the  curve,  and  the 
inner  rail  put  in  its  place.  This  furnishes  almost  new  wear- 
ing surfaces  to  the  wheel,  and  the  life  of  the  rails  is  greatly 
prolonged. 

1675.  Care  of  Curved  Track. — As  curved  track 
offers  greater  resistance  and  greater  danger  to  passing 
trains  than  straight  track,  special  eff"ort  and  pains  should  be 
taken  to  maintain  it  in  perfect  order.  All  trackmen  know 
that  a  low  spot  on  a  curve  will  cause  every  car  in  a  train  to 


1102 


TRACK  WORK. 


lurch  heavily  towards  the  low  side.  By  careful  watching, 
and  by  prompt  and  thorough  repairs, 
curved  track  may  be  kept  in  perfect  or- 
der. It  is  highly  important  that  the  ele- 
vation of  the  outer  rail  be  kept  uniform, 
and  no  foreman,  however  experienced, 
should  place  dependence  upon  his  eye  in 
estimating  curve  elevation. 

Both  the  civil  engineer  and  the  track 
forepian  will  do  well  to  cultivate  each 
other,  the  engineer  imparting  theoretical 
knowledge  in  exchange  for  practical 
knowledge.  The  result  will  certainly  pro- 
mote mutual  respect  and  enhance  the 
efficiency  of  both. 


FROGS   AND    SWITCHES. 


FROGS. 
1676.  Turnouts. — A  turnout  is  a 
device  for  enabling  an  engine  and  train  to 
pass  from  one  track  to  another.  It  con- 
sists of  two  lines  of  rails  a  b  and  c  d  (see 
Fig.  522),  so  laid  as  to  form  a  reversed 
curve  uniting  the  two  tracks  A  B  and 
C  D.  The  several  parts  of  a  turnout  are 
as  follows:  The  switch  rails  r  /  and 
gh^  the  frogX',  and  the  two  guard-rails 
/  m  and  n  o.  The  stationary  ends  c  and 
g  of  the  switch  rails  are  called  the  heels, 
and  the  movable  ends  /  and  h  are  called 
the  toes.  The  distance  /  /»,  through 
which  the  toes /"and  //  move,  is  called  the 
throw.  The  throw  must  equal  the  width 
of  the  head  of  the  rail,  with  sufficient 
additional  width  to  allow  the  flanges  of  the 
wheels  to  pass  freely  between  the  main  rails  r  s  and  /  ti  and 


TRACK  WORK.  1103 

the  turnout  rails  a  b  and  c  d.  The  throw  on  tracks  of  stand- 
ard gauge  is  5  inches;  that  is,  the  toes /"and  //  are  moved  5 
inches  from  their  original  position  in  the  main  track  in 
forming  the  turnout  curve  on  which  the  train  is  to  pass 
from  the  main  track  ^  ^  to  the  siding  C  D. 

The  movement  of  the  switch  rails  is  effected  by  means  of 
a  lever. 

1677.  The  Frog. — The  frog  is  a  device  by  means  of 
which  the  rail  at  the  turnout  curve  crosses  the  rail  of  the 
main  track.  The  frog  shown  in  Fig.  523  is  made  of  rails 
having  the  same  cross-section  as  those  used  in  the  track. 
Its  parts  are  as  follows:  The  wedge  shaped  part  A  is  the 
tongue,  of  which  the  extreme  end  a  is  the  point.  The 
space  b,  between  the  ends  c  and  ^^of  the  rails,  is  the  mouth, 


Fig.  533. 

and  the  channel  which  they  form  at  its  narrowest  point  e  is 
the  throat.     The  curved  ends/  and  g  are  the  wings. 

That  part  of  the  frog  between  A  and  A'  is  called  the 
heel.  The  width  h  of  the  frog  is  called  its  spread.  Holes 
are  drilled  in  the  ends  of  the  rails  c^  d,  k,  and  /  to  receive  the 
bolts  used  in  fastening  the  rail  splices,  so  that  the  rails  of 
which  the  frog  is  composed  form  a  part  of  the  continuous 
track. 

1678.  The  Frog  Point.— The  theoretical  point  of 
frog  a'  (see  Fig.  523)  and  the  actual  point  a  are  quite  dis- 
similar. The  reason  for  making  a  the  point  of  frog  is  that 
if  the  theoretical  and  actual  point  of  frog  were  the  same, 
the  point  would  be  so  small  that  the  first  blow  inflicted  by 
a  passing  locomotive  or  car  would  completely  destroy  it. 
The  frog  point  is  accordingly  placed  at  rt,  where  its  width 
is  about  \  of  an  inch. 


1104 


TRACK  WORK. 


1(>79.  The  Frog  Number. — The  number  of  a  frog  is 
the  ratio  of  its  length  to  its  breadth,  i.  e.,  the  quotient  of 
its  length  divided  by  its  breadth. 

Thus,  in  Fig.  523,  if  the  length  a'  /,  from  point  to  heel  of 
frog  is  5  feet,  or  60  inches,  and  the  breadth  h  of  the  heel  is 
15  inches,  the  number  of  the  frog  is  the  quotient  of  GO  -r-  15  = 
4.  Theoretically,  the  length  of  the  frog  is  the  distance 
from  a  to  the  middle  point  of  a  line  drawn  from  k  to  /; 
practically,  we  take  as  the  length  the  distance  from  a  to  /. 
As  it  is  often  difficult  to  determine  the  exact  point  a  of  the 
frog,  a  more  accurate  method  of  determining  the  frog  num- 
ber is  to  measure  the  entire  length  d  I  of  the  frog  from  mouth 
to  heel,  and  divide  this  lefigth  by  the  sum  of  the  mouth  width 
b  and  the  heel  width  h.  The  quotient  will  be  the  exact  number 
of  the  frog. 

For  example,  if  in  Fig.  523,  the  total  length  d  I  oi  the 
frog  is  7  feet  4  inches,  or  88  inches,  and  the  width  /;  is  15 
inches,  and  the  width  b  of  the  mouth  is  7  inches,  then  the 
frog  number  is  88  -=-  (15  -f  7)  =  4.  Frogs  are  known  by 
their  numbers.     That  in  Fig.  523  is  a  No.  4  frog. 

1680.     The    Frog   Angle. — The    frog   angle    is  the 

angle  formed  by  the  gauge  lines  of  the  rails,  which  form  its 
tongue.  Thus,  in  Fig.  523,  the  frog  angle  is  the  angle  la'  k. 
The  amount  of  the  angle  may  be  found  as  follows:  The 
tongue  and  heel  of  the  frog  form  an  isosceles  triangle  (see 
Fig.  524).     By  drawing  a  line  from  the  point  a  of  the  frog 


to  the  middle  point  b  of  the  heel  c  d,  we  form  a  right-angled 
triangle,    right-angled  at    b.     The  perpendicular  line  a  b. 


TRACK  WORK. 


1105 


bisects  the  angle  a,  and,  by  rule  5,  Art.  754,  we  have  tan 

be 
^  a  =:  —J.     The  dimensions  of  the  frog  point  given  in  Fig. 

52-4  are  not  the  same  as  those  given  in  Fig.  523,  but  their 
relative  proportions  are  the  same,  viz.,  the  length  is  four 
times  the  breadth.  The  length  a  ^  .—  4,  and  the  w^idth 
c  d  =  1;  hence,  d  c  —  ^.     Substituting  these  values,  we  have 

tan  ^  rtr  =  f  =  ^  =  0. 125.     Whence,    ^  a  =  7°  7^',  and  a  = 

14°  15';  that  is,  the  angle  of  a  No.  4  frog  is  14°  15'. 

Frog  numbers  run  from  4  to  12,  including  half  numbers, 
the  spread  of  the  frog  increasing  as  the  number  decreases. 

1 681 .     Classification  and  Description  of  Frogs. — 

Frogs,  as  manufactured  to-day,  are  of  two  classes,  viz.,  sti^ 
frogs  and  sprtng-rail  frogs.  Each  has  advantages  peculiar 
to  itself,  which  specially  adapt  it  to  certain  situations. 
Stiff  frogs  contain  much  less  material  and  require  less 
shop  work  than  spring  frogs.  For  a  given  angle  a  stiff 
frog  requires  less  space,  and  hence  is  better  adapted  to  yard 
work  than  spring-rail  frogs.  They  are  more  simply  con- 
structed than  spring  frogs,  and  can  be  made  at  any  well- 
equipped  machine  shop. 

Spring-rail  frogs,  because  of  their  furnishing  an  unbroken 
surface  to  the  wheel  treads,  are  particularly  adapted  to  the 
heavy  traffic  of  a  trunk  line. 


Pig.  625. 

Figs.  525  and  526  represent  the  best  types  of  stiff  frogs. 
The  frog  shown  in  Fig.  525  is  called  a  plate  frog.  The 
rails  composing  the  frog  are  fastened  to  a  plate  of  wrought 
iron  or  steel  a  c  d  b  by  means  of  rivets  through  the  rail 
flanges,  as   shown    in  the   figure.     Square   holes   r,  f  are 


1106  TRACK  WORK. 

punched  in  the  plate  to  receive  the  railroad  spikes,  which 
are  driven  into  the  cross-ties  supporting  the  frog,  holding  it 
firmly  in  place.  Plate  frogs  are  perfectly  rigid,  and  by  many 
railroad  men  are  considered  inferior  to  the  keyed  frog, 
shown  in  Fig.  526,  which  is  somewhat  flexible  and  better 


(fix  iff  r£fe\ 


^     B 


Fig.  526. 


suited  to  yard  work  where  the  curves  are  sharp  and  the  frog 
angles  correspondingly  large. 

In  this  frog,  the  pieces  of  rails  a  and  I?,  forming  the  point, 
are  dovetailed  together  and  secured  by  heavy  rivets.  To 
retain  the  full  strength  and  durability  of  the  steel,  all  the 
parts  are  fitted  without  being  heated,  excepting  the  wings, 
which  are  bent  at  a  very  low  heat.  Hence,  the  strength  of 
the  rails  is  in  no  respect  diminished,  and  the  method  of 
securing  the  parts  together  has  advantages  over  bolts  or 
rivets  passing  through  the  webs  or  flanges  of  the  rails,  as 
there  is  nothing  which  can  come  in  contact  with  the  wheel 
flanges.  From  its  peculiar  construction,  it  has  the  same 
elasticity  as  the  rails  in  the  track,  which  makes  it  an  easy 
riding  frog,  more  durable  than  a  rigid  frog,  and  less  liable 
to  injury  from  uneven  ballasting.  It  presents  little  obstruc- 
tion to  tamping,  and,  when  fastened  into  the  track  with  the 
usual  angle  splices,  it  is  firm,  stable,  and  free  from  any 
tendency  to  jump  or  move. 

The  parts  are  bound  together  by  heavy  wrought-iron 
clamps  c  and  d^  shown  in  the  cross-sections  A  and  />,  A 
being  a  cross-section  through  the  first  clamp  and  B  one 


TRACK  WORK.  1107 

through  the  second  clamp.  These  clamps  are  tightened  by 
means  of  beveled  split  keys,  or  wedges,  e  and/",  the  ends  of 
the  clamps  being  bent  over  a  form  to  an  exact  angle,  at  one 
end  to  fit  the  brace  blocks  k  and  k'  on  the  outside  of  the 
rail,  and  at  the  other  end  to  fit  the  beveled  keys,  which  are 
driven  into  the  spaces  between  the  end  of  the  clamp  and  the 
smaller  brace  blocks  /,  /'.  The  keys  lie  on  the  flange  of  the 
rail,  which  prevents  them  from  dropping  down  in  case  they 
loosen.  The  flange  way  between  the  frog  point  and  the  wing 
rails  is  maintained  by  iron  throat-pieces  g,  h,  g\  and  h\ 
which  fit  the  rails  perfectly,  and,  extending  beyond  the 
point,  thoroughly  brace  and  stay  it  against  lateral  stresses. 
After  tlie  keys  are  driven  to  the  extent  necessary  to  bind 
the  parts  solidly  together,  the  split  ends  are  spread  to 
prevent  the  keys  from  working  out. 

The  throat-pieces,  as  well  as  the  brace  blocks,  are  effect- 
ually prevented  from  sliding  out  of  their  positions.  The 
clamps  are  firmly  secured  to  the  flanges  of  the  rails,  and  the 
only  movable  pieces  in  the  frog  are  the  keys  which,  being 
thicker  on  their  lower  edge  (owing  to  being  beveled  un- 
equally), together  with  the  angles  of  the  clamps,  prevent 
the  keys  from  working  upwards.  Trackmen,  when  inspect- 
ing track,  should  always  examine  the  frogs,  and  any  key 
loosened  by  the  wearing  of  the  parts  should  be  tightly  driven, 
and  the  split  end  spread  open.  Unless  a  key  is  loose  it 
should  never  be  hammered. 

A  standard  type  of  a  spring-rail  frog  of  keyed  pattern 
is  shown  in  Fig.  527.  For  main  line  tracks,  and  especially 
for  those  sections  where  the  heavy  traffic  moves  principally 
in  one  direction,  the  spring-rail  frog  is  recommended.  It 
gives  to  the  main  line  the  smoothness  of  an  unbroken  track; 
it  is  simple  in  its  construction,  thoroughly  substantial,  and  is 
placed  in  position  with  the  least  amount  of  labor. 

As  shown  in  the  figure,  the  fixed  parts  of  the  patent  keyed 
spring  frog  2st.  bound  together  by  two  heavy  clamps  rt  and  b^ 
shown  in  the  details  A  and  B,  which  are  sections  through 
the  clamps  zX.  C  D  and  E  F.  The  parts  within  the  clamps 
are  secured  by  split  keys  or  wedges  c  and  d.     The  frog  point 


1108 


TRACK  WORK. 


G  is  made  of  two 
pieces  of  steel  rail 
fitted  and  dovetailed 
together  by  machin- 
ery, without  being 
heated,  and  securely 
riveted  together.  The 
flange  way  between 
the  point  and  wing 
rails  is  maintained  by 
closely  fitting  iron 
throat-pieces  e  and  f 
(shown  in  the  detail 
sections  A  and  B^, 
which  are  prevented 
from  slipping  by  rivets 
and  pins  through  the 
rails.  The  clamps 
have  side  notches  g 
and  g'  at  one  end 
(shown  in  detail  at  Z), 
which  engage  with 
notches  in  the  flange 
at  the  frog  point,  and 
prevent  the  clamps 
from  slipping  down, 
even  if  loose.  The 
other  end  of  the  clamp 
is  bent  over  a  form  to 
an  exact  angle  to  fit 
the  beveled  split  key, 
which  is  driven  into 
the  space  between  the 
clamp  and  the  block, 
which  is  fitted  and  se- 
cured to  the  side  wing 
rail.  When  the  key  is 
driven,    the    parts    of 


/ 


V*      "j       ^      ii  ,    Lil    |ii| 


.\.\. 


i— -- 


/' 


TRACK  WORK.  1109 

the  frog  are  tightly  bound  together,  and  the  key  resting 
upon  the  flange  of  the  rail  is  prevented  from  working  down 
and  loosening.  The  outer  end  of  the  clamp  is  secured  by 
clips,  which  are  riveted  to  the  flange  of  the  rail. 

In  case  the  parts  of  the  frog  become  loosened  by  wear, 
they  may  be  tightened  by  driving  the  wedge  further  in  and 
spreading  the  split  ends  so  as  to  hold  the  key  firmly  in  place. 

That  part  of  the  flange  of  the  spring  rail  next  to  the  frog 
point  is  planed  off,  allowing  the  head  of  the  spring  rail  to 
lie  close  to  the  frog  point,  forming  almost  a  continuous  rail 
and  fully  accommodating  all  classes  of  wheels  passing  the 
frog.  Powerful  springs  H  and  K  hold  the  spring  rail  firmly 
against  the  frog  point,  and  the  slide  arm  //,  which  is  held  in 
place  by  the  clip  k,  attached  to  the  slide  plate  (shown  in  the 
detail  section  M  N),  prevents  the  spring  rail  from  rising  up 
or  moving  out  too  far.  The  usual  length  of  this  spring  frog 
for  any  angle  is  15  feet. 

1682.  Crossing  Frogs. — Where  one  railroad  crosses 
another  at  grade,  frogs  of  special  design,  called  crossing 
frogs,  are  required.  They  are  of  various  patterns,  depend- 
ing upon  the  angle  of  the  crossing  and  the  importance  of 
the  line.  In  Fig.  528  a  cut  is  given  of  a  standard  crossings 
which  embodies  the  best  features  as  determined  by  ex- 
perience. 

This  crossing  is  made  of  the  best  quality  steel  rails,  fitted 
with  exactness.  The  points  are  mitered,  dovetailed,  welded, 
or  forged  out  of  solid  rails,  the  angle  of  the  crossing  and  the 
requirements  of  the  case  determining  which  method  is  the 
most  practicable.  The  rails  are  mounted  on  strong  wrought- 
iron  bed-plates  A,  B,  etc.,  to  which  they  are  securely  riveted 
through  the  flanges  of  the  rails.  The  guard-rails  a,  b,  c,  and 
d,  inside  the  intersecting  tracks,  extend  unbroken  on  all 
sides,  and  extend  outside  the  frog  points  so  as  to  guide  the 
trucks,  causing  them  to  pass  squarely  through  the  crossing. 

At  all  the  angles  the  flange  way  is  completely  filled  by 
wrought-iron  throat  fillers  c,  /,  and  c,  which  are  shaped  to 
exactly  fit  the  rails. 


1110 


TRACK  WORK. 


All  the  corners  are  braced  with  heavy  wrought-iron 
braces^,  h,  k^  etc.,  forged  to  shape  and  planed  to  fit  solid 
in  the  fishing  spaces  of  the  rails.  Strong  bolts,  /,  m,  etc., 
passing  through  the  webs  of  the  rails,  the  throat  fillers, 
and  corner  braces,  bind  the  parts  of  the  crossing  firmly  to- 
gether. 

All  the  inside  splice  joints  are  provided  with  solid  iron 
throat  blocks  «,  o  between  the  rails  in  addition  to  the  usual 
splice  bars.  The  splice  bolts  /  and  q  pass  through  splice 
bar,  throat  block,  and  rail,  binding  all  securely  together. 
Care  should  be  taken  that  no  bolts  project  through  the  bed- 
plates, necessitating  the  cutting  of  pockets  in  the  crossing 
timbers  to  receive  the  bolt  heads,  as  increased  decay  is  sure" 
to  follow. 


1683.     Replacing    Frogs. — A  replacing  frog   is  a 

device  for  replacing  derailed  cars  upon  the  track.  Such  a 
frog  must  combine  portability  and  great  strength.  It  must 
be  flexible  and  compact,  and  of  simple  construction. 

The  replacing  frog  shown  in  Fig.  529  combines  practically 
all  of  these  qualities.     This  frog  consists  of  a  heavy  steel 


Fig.  529. 

bar  a  slightly  curved.  The  bar  is  bolted  at  one  end  to  a 
heavy  steel  hook  b  which  hooks  under  the  head  of  the  rail. 
The  joint  r,  connecting  the  bar  and  hook,  allows  the  frog  to 
be  placed  in  any  desired  position.  The  end  d  oi  the  bar  is 
hooked  and  pointed.  In  using  the  frog,  the  hook  b  is  first 
adjusted;  the  end  d  is  then  placed  directly  in  front  of  the 
wheel  of  the  derailed  truck,  and  the  point  d  of  the  bar 
driven   into  the   cross-tie    with  a   sledge.     This  holds   the 


TRACK  WORK.  1111 

replacing  frog  rigidly  in  place.  A  replacing  frog  is  placed  in 
position  on  both  rails,  and  the  car  pulled  on  to  the  track 
with  a  locomotive.  Where  the  trucks  are  slewed  crosswise 
to  the  track,  the  car  must  be  jacked  up  and  the  trucks 
straightened  before  placing  the  frogs. 


SWITCHES. 

1 684.  Classification  of  Switches. — Although  there 
have  been  many  different  kinds  of  switches  devised,  only  two 
of  them  have  ever  been  in  general  use;  viz.,  stub  and  split, 
or  point,  switches.  Stub  switches  are  now  rarely  used  on 
first-class  roads,  even  in  yards,  the  split  or  point  switch  hav- 
ing entirely  supplanted  them.  It  is  estimated  that  50  per 
cent,  of  the  derailments  on  American  lines  have  been  direct- 
ly chargeable  to  the  defects  of  the  stub  switch. 

The  principal  defect  in  the  stub  switch  lies  in  the  open 
joint  at  the  head-block.  In  passing  over  this  joint,  each 
wheel  delivers  a  heavy  blow  on  the  ends  of  the  rails  at  the 
point,  which  not  only  batters  the  rails  but  also  causes  a 
heavy  jolt  to  the  car,  injurious  to  the  rolling  stock  and  caus- 
ing much  discomfort  to  passengers.  Stub  switches  are 
more  liable  to  misplacement  than  split  switches,  and  there  is 
the  constantly  recurring  need  of  recutting  the  ends  of  the 
rails  at  the  head-block,  to  provide  for  expansion  and  for  the 
removal  of  battered  ends. 

1685.  The  Stub  Switch.— The  essential  parts  of  a 
stub  switch  are  shown  at  A  in  Fig.  530.  The  rails  a  b  and 
c  d  are  the  switch  rails  placed  for  the  turnout  track. 
Their  position  when  placed  for  the  main  track  is  indicated 
by  dotted  lines  at  e  and/".  The  switch  rails  are  commonly 
used  in  lengths  of  30  feet,  the  standard  rail  length,  of  which 
only  22  feet  are  free  to  move  or  slide,  the  remaining  8  feet 
being  spiked  to  the  ties,  as  shown  in  the  figure.  The  mov- 
ing portions  of  the  switch  rails  are  held  in  place  by  rods  g^  h, 
k,  and  /,  called  s^vitch  rods.  These  rods  keep  the  switch 
rails  at  proper  gauge,  and  serve  the  purpose  of  track  spikes. 


1112 


TRACK  WORK. 


0 

^fe^M 

1 

F 

' 

^ 

TRACK  WORK.  1113 

The  first  switch  rod  g  is  called  the  head  rod.  It  extends 
outside  the  rails,  and  by  means  of  the  connection  rod  in, 

it  is  attached  to  the  lever  n  of  the  switch  stand,  by  means 
of  which  the  switch  rails  are  moved  from  their  connection 
with  the  main  track  rails  o  and  />,  to  a  connection  with  the 
turnout  rails  ^  and  r.  This  movement  of  the  switch  rails  is 
termed  throwing  the  switch. 

The  switch  stand,  and  connection  and  head  rods  of  this 
switch  are  shown  in  detail  at  B.  The  switch  stand  Z>  con- 
sists of  a  cast-iron  plate  s  to  which  is  cast  a  semicircular 
lug  /.  A  hole  in  this  lug  receives  a  pin,  which  is  attached 
to  the  end  of  the  lever  n.  The  connection  rod ;//  is  attached 
to  the  lever  by  means  of  the  pin  u,  and  is  held  in  place  by  a 
nut.  The  lever  handle  is  slotted,  and  when  the  switch  is 
set  for  either  track,  the  slot  fits  over  a  staple  v,  projecting 
above  the  lever  far  enough  to  receive  a  padlock  w  which 
locks  the  switch. 

The  switch  rods  clamp  the  switch  rails  firmly,  as  shown  at 
X.  The  head  chair,  shown  at  E,  is  of  cast  iron,  and  con- 
tains sockets^,  y,  into  which  the  ends  of  the  main  and  turn- 
out rails  o  and  q  securely  fit.  The  lateral  movement  of  the 
switch  rail  is  limited  by  the  lugs  z  and  z\  which  are  cast  into 
the  chair.  The  head  chair  is  usually  fastened  to  the  head- 
block  with  track  spikes. 

The  cross-tie  F,  which  supports  the  head  chairs  and  switch 
stand,  is  called  the  head  block.  The  head  block  and  all 
other  switch  ties  should  be  of  hard  wood — oak  preferably. 
The  ties  under  the  switch  rails  should  be  of  sawed  timber, 
so  as  to  present  a  smooth  even  surface  for  the  sliding 
rails. 

This  type  of  switch  stand  is  equally  well  suited  to  split 
switches,  and  on  account  of  its  compactness  is  especially 
suited  to  yard  work. 

The  stub  switch  is  cheaper  than  the  split  switch,  and  for 
tracks  owned  by  private  concerns,  it  serves  very  well ;  but 
for  railroads  doing  a  regular  freight  and  passenger  business, 
it  is  not  only  out  of  date,  but  should  be  condemned  as 
unsafe. 


1114 


TRACK  WORK.  .1115 

1686.  Split,  or  Point,  Switches.— The  split,  or 
point,  switch  does  away  with  the  open  joint  at  the  head 
block  and  gives  a  continuous  bearing  to  the  car  wheels.  The 
two  common  types  of  split  switches  are  shown  in  Figs.  531 
and  532.  In  Fig.  531,  the  rails  A  A'  and  ^^' are  called  the 
stock  rails.  In  the  split  switch,  the  heels  and  toes  of  the 
switch  rails  are  exactly  the  reverse  of  those  in  the  stub 
switch,  i.  e. ,  the  heels  in  the  split  switch  are  in  the  places 
occupied  by  the  toes  in  the  stub  switch.  The  stock  rails  are 
spiked  throughout  their  entire  length.  The  switch  rails 
C  C\  D  D'  are  usually  15  feet  in  length  for  all  turnouts 
excepting  those  in  yards  where  limited  space  requires  very 
sharp  curves,  and  switch  points  12  feet  in  length,  or  even  less, 
are  used  instead. 

The  switch  rails  are  usually  straight  and  planed  down  so 
as  to  fit  closely  to  the  stock  rails  for  6  or  7  feet.  The  points 
C  and  D  are  planed  down  to  a  thin  edge,  the  web  of  the 
switch  rail  being  grooved  so  as  to  fit  under  the  head  of  the 
stock  rail. 

The  base  of  the  switch  rail  is  planed  so  that  it  fits  snugly 
against  the  upper  part  of  the  base  of  the  stock  rail.  The  ex- 
treme points  of  the  switch  rails  are  slightly  below  the  level 
of  the  stock  rails,  so  that  the  wheel  treads  do  not  come  in 
contact  with  them  until  their  size  and  strength  are  sufficient 
to  stand  the  hard  pounding  which  all  switches  receive. 

The  slide  plates  a,  b,  c^  d^  e^  and /"extend  under  the  stock 
rails  and  points,  and  are  spiked  to  the  cross-ties.  The 
switch  rods  g,  h,  k,  /,  and  m  are  of  wrought  iron,  and  of  such 
dimensions  as  the  size  and  weight  of  the  rail  require.  They 
are  fastened  to  the  switch  rails  in  various  ways.  In  Fig.  531, 
the  connection  is  made  by  means  of  cast  steel  sockets  which 
are  belted  to  the  webs  of  the  rails.  The  switch  rod  g,  con- 
necting directly  with  the  switch  stand,  is  called  theliead  rod, 
and  is  shown  in  detail  at  E.  The  cast-steel  sockets  //  and  n' 
are  longer,  and  extend  low  enough  to  permit  the  head  rod  to 
pass  under  the  rails,  as  shown  in  the  detail.  The  head  rod 
is  fastened  to  each  socket  with  two  bolts,  while  the  other 
switch  rods  are  single  bolted. 


1116  .  TRACK  WORK. 

The  stock  rails  are  spiked  only  on  the  outsides  of  the  rails, 
and  to  prevent  the  rails  from  getting  out  of  line,  the  slide 
plates  are  bent  upwards  at  the  outside  of  the  rail,  forming 
the  lip  o  (see  detail  at  7^),  which  holds  the  rail  brace  p  solidly 
against  the  stock  rail. 

The  connection  rod  q  is  fastened  at  one  end  to  the  head 
rod  and  at  the  other  end  to  the  crank  r  of  the  switch  stand, 
shown  in  detail  at  G.  The  switch  stand  rests  upon  two 
cross-ties  s  and  s\  being  securely  fastened  to  them  either 
with  bolts  or  track  spikes.  The  switch  stand  consists  of  the 
column-shaped  support  /,  the  lever  «,  used  in  throwing  the 
switch,  the  target  ?',  and  the  crank-shaft  r. 

The  target  v  consists  of  two  rectangular  pieces  of  sheet 
iron  fastened  to  the  target  rod  at  right  angles  to  each  other. 
One-half  of  the  target  is  usually  painted  white,  indicating 
safety,  and  the  other  half  red,  indicating  danger.  They 
are  so  adjusted  that  an  open  switch  always  indicates 
danger. 

The  lever  u  carries  a.  cam  or  eccentric-shaped  disk  u>  which, 
when  in  the  position  u,  fits  between  lugs  x\  the  lugs  are 
bolted  to  the  pedestal  t,  and  form  a  part  of  the  rigid  stand. 
When  the  lever  is  in  the  position  //,  the  switch  may  be  locked, 
holding  the  switch  firmly  in  place.  To  throw  the  switch, 
raise  the  lever  to  the  position  u'.  This  releases  the  cam  w 
from  the  lug  x,  and  the  lever  being  clamped  to  the  target 
rod  or  shaft  J,  any  movement  of  the  lever  u  is  communi- 
cated to  the  crank  r,  which,  by  means  of  the  connection  rod 
g,  acts  directly  upon  the  switch  rails. 

The  throw  of  the  switch  is  from  4^  to  5  inches.  The  rail 
braces  /  are  usually  of  forged  steel,  though  some  are  still 
made  of  cast  iron. 

1687.  Safety  Switches.  — When  a  train  passes  from 
the  main  track  to  the  side  track,  it  necessarily  passes 
the  points  of  the  switch  first.  Such  a  switch  is  called  a 
facing  switcti.  When,  on  the  other  hand,  a  train  passes 
from  the  side  track  to  the  main  track,  it  passes  the  frog 
first.      Such  a  switch  is  called  a  trailing  switch. 


TRACK  WORK. 


1117 


1118  TRACK  WORK. 

William  Lorenz,  chief  engineer  of  the  Philadelphia  and 
Reading  Railroad,  has  the  credit  of  designing  a  self-acting 
switch,  which  is  provided  with  a  powerful  spring  that  holds 
the  switch  points  firmly  against  the  stock  rail,  thus  keeping 
the  main  track  constantly  unbroken.  With  the  switch 
points  in  this  position,  a  train  can  make  a  trailing  switch, 
the  wheel  flanges  forcing  the  switch  open  as  they  pass  from 
the  side  to  the  main  track.  As  the  spring  is  constantly  act- 
ing, each  wheel  throws  the  switch,  which  instantly  resumes 
its  position  for  the  main  track. 

Such  a  switch  is  called  a  Lorenz,  or  safety  switch, 
and  is  shown  in  Fig.  532.  With  the  exception  of  the  spiral 
spring'^,  which  is  attached  to  the  head  rod  and  holds  the 
switch  point  a  against  the  stock  rail  b,  this  switch  is  similar 
to  that  shown  in  Fig.  531. 

The  switch  rods  c,  d,  and  e,  instead  of  being  single  rods 
"W^ith  arms  at  their  ends  for  attaching  them  to  the  switch 
rails,  as  in  Fig.  531,  have  a  trussed  center  piece,  shown  in 
detail  at  B,  composed  of  two  bars/"  and  g,  riveted  together 
and  leaving  between  them  just  space  enough  to  allow  the 
ends  of  the  arms  //  and  k  to  move  as  the  switch  is  thrown 
from  one  side  of  the  track  to  the  other,  the  arms  pivoting 
on  the  rivets  /  and  in  at  the  end  of  the  center  piece. 

This  form  of  switch  rod  combines  flexibility  with  great 
strength,  insuring  easy  movement  to  the  switch  and  great 
resistance  to  the  severe  stresses  which  are  continually 
brought  to  bear  against  it. 

The  switch  rods  are  bent  downwards  near  the  arms,  bring- 
ing them  nearly  on  a  level  with  the  top  of  the  tie,  where 
they  are  less  exposed  to  injury  from  derailed  cars  or  from 
broken  parts  of  the  cars,  such  as  brake  rods  or  beams,  which 
dragging  on  the  ties  frequently  catch  in  switch  rods,  doing 
much  harm. 

The  safety  switch,  shown  in  Fig.  532,  is  of  a  pattern  com- 
monly used  in  yards  and  terminals.  The  switch  points  vary 
in  length  from  7^  feet  to  12  feet,  the  former  fitting  all  frog 
numbers  as  high  as  7,  and  the  latter  serving  for  frogs  of  all 
numbers. 


TRACK  WORK.  1119 

The  advantages  of  this  switch  are  its  compactness,  requi- 
ring little  more  than  half  the  space  of  an  ordinary  switch; 
lightness,  which  insures  easy  handling,  and  its  adaptation  to 
sharp  curves  which  abound  in  yards  and  terminals.  The 
short  points  permit  of  trailing  switches  equally  as  well  as 
facing  switches,  as  the  planed  portion  of  the  points  is  short, 
and,  consequently,  carries  a  much  shorter  proportion  of  the 
wheel  base  of  an  engine  or  car  than  the  switch  of  the  standard 
length.  The  short  points  also  require  lighter  springs  than 
the  standard  lengths,  and  are  much  easier  cleared  of  snow. 
The  details  of  the  switch  are  practically  the  same  as  those  of 
the  switch  shown  in  Fig.  531,  which  were  fully  described.  A 
common  yard  stand  suitable  for  this  switch  is  shown  in  both 
plan  and  elevation  at  C.  The  target  is  about  4  feet  above  the 
ground,  and  is  provided  with  an  attachment  for  signal 
lamp.  The  lever  is  hinge-jointed,  and  in  throwing  the  switch, 
the  lever  is  brought  into  a  horizontal  position,  resting  on 
the  semicircular  iron  latch  plate  E.  In  the  edge  of  this 
plate  are  two  slots  n  and  o^  into  which  the  lever  hinges  after 
the  switch  is  thrown.  Lugs/  and  q  at  the  sides  of  the  slots, 
limit  the  lateral  movement  of  the  lever.  The  switch  stand 
is  secured  to  the  head-block  by  either  bolts  or  track  spikes, 
usually  the  latter. 

1688.  Three-Throw  Switches. — A  cut  of  a  three- 
throw,  or  double-throw,  switch  is  given  in  Fig.  533.  The 
type  is  that  of  the  ordinary  stub  switch,  except  that  the  mov- 
ing or  switch  rails  serve  two  turnout  tracks  instead  of  but 
one.  The  head  chair  A  is  usually  of  cast  iron  and  contains 
sockets  rt,  ^,  and  c  (see  detail  B)  for  the  fixed  rails  d^  e,  and/". 

The  switch  rails  ^  and  h  have  a  total  lateral  movement  at 
the  head  chairs  of  from  10  to  12  inches,  depending  upon  the 
dimensions  of  the  rails.  Their  lateral  movement  is  fixed  by 
the  lugs^,  k  on  the  head  chairs. 

The  switch  stand  is  shown  in  elevation  at  C,  and  in  plan 
at  D.  The  three  positions  of  the  switch  are  fixed  by  the 
slots  /,  w,  and  o  in  the  latch  plate  into  which  the  switch  lever 
hinges. 


1120 


TRACK  WORK. 


A  more  comprehensive  idea  of  a  double-throw  switch  may 
be  obtained  from  the  detail  given  at  E,  which  shows  to  a  re- 


FIG.  KM. 


duced  scale  the  switch  and  both  turnout  curves  with  main 
rail  frogs/  and  v,  and  the  crotcli  frog  r,  by  means  of  which 


TRACK  WORK. 


1121 


the  outer  rails  of  the  turnout  curves  cross  each  other.  The 
turnout  curves  of  a  double-throw  switch  are  usually  of  the 
same  degree,  which  brings  the  crotch  frog  in  the  middle  of 
the  main  track. 

The  defects  of  the  stub  switch  already  described  should 
prevent  its  use.in  the  main  track  at  yards,  and  at  terminals 
where  trains  move  slowly,  as  well  as  at  intermediate  points 
where  trains  run  at  top  speed. 

A  double-throw  split  switch  has  been  invented  and  used 
in  a  limited  way,  and  though  a  perfect  switch  so  far  as  mech- 
anism is  concerned,  it  is  much  more  expensive  and 
complicated  than  a  double-throw  stub  switch,  and  is  not 
enduring. 

The  object  of  the  double-throw  switch,  viz.,  economy  of 
space,  is  practically  attained  by  substituting  two  single  split 


Fig.  534. 

switches,  placed  as  close  together  as  is  consistent  with  their 
safe  operation.  Such  an  arrangement  is  shown  in  Fig.  534, 
in  which  a  a'  and  b  b'  are  the  rails  of  the  main  track.  A 
7°  30'  turnout  curve  c  e  \^  laid  out  to  the  right  of  the  main 
track.  This  calls  for  a  head  block  at  c  and  a  No.  9  frog  at/". 
A  17°  turnout  curve  g  in  is  next  laid  out  to  the  left  of  the 
main  track,  with  its  P.  C.  located  so  as  to  bring  the  head 
block  ^  of  the  second  switch  far  enough  from  the  heel  d  of 
the  first  switch  to  afford  suflEicient  room  for  operating  the 
second  switch.  This  calls  for  a  No.  6  frog  at  k  and  a  No.  5^ 
crotch  frog  at  /. 

1689.     Derailing  Switches.— A  derailing  switch 

is  a  device  for  derailing  cars,  and  so  preventing  them  from 
accidentally  running  out  of  the  siding  on  the  main  track. 


1122 


TRACK  WORK. 


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TRACK  WORK.  1123 

They  are,   of  course,   needed  only  for   sidings   built   with 
grades  descending  towards  the  switch. 

An  effective  type  of  a  derailing  switch  is  shown  at  A  in 
Fig.  535.  It  consists  of  a  single  switch  rail  a,  which  is 
hinged  at  the  rail  joint  d.  The  switch  point  c  is  beveled,  as 
shown  in  the  detail  at  C.  When  the  switch  is  closed,  this 
beveled  switch  point  rests  against  the  outside  rail  of  the 
siding,  which  is  bent  at  an  angle  corresponding  to  the  bevel 
of  the  switch  point  and  shown  at  d,  forming  a  lap  switch. 
When  the  switch  is  open,  the  switch  point  rests  against  the 
guard  rail  e,  the  end  of  which  is  beveled  to  form  a  seat  for 
the  switch  point.  The  beveled  ends  of  both  track  and 
guard  rail  rest  upon  a  wrought-iron  head  chair  /,  shown  in 
detail  at  C,  upon  which  the  switch  point  slides. 

This  switch  is  connected  with  and  operated  by  the  move- 
ment of  the  main  line  switch  B.  The  figure  shows  the 
switch  set  for  the  main  line,  and  the  derailing  switch  set  to 
throw  from  the  track  a  car  moving  out  of  the  siding. 

The  derailing  switch  is  operated  as  follows:  A  bell-crank 
g  is  pivoted  to  a  cross-tie,  with  one  end  of  the  crank  at- 
tached to  the  head  rod  of  the  switch  B.  To  the  other  end 
of  the  crank  is  attached  a  strong  steel  wire  which  extends  to 
a  sheave  //,  directly  opposite  the  derailing  switch  A,  and 
thence  to  an  eye  k,  as  shown  in  detail  at  C  and  D,  in  the 
end  of  the  head  rod.  This  wire  is  kept  taut,  so  that  any 
movement  of  the  switch  B  is  communicated  directly  to  the 
switch  rail  a.  The  connection  rod  /  is  attached  to  the  short 
arm  in  of  the  switch  lever;  and  when  the  switch  is  set  for 
the  main  line  E  E,  as  shown  in  the  figure,  the  resulting 
stress  in  the  wire  is  transmitted  to  the  short  arm  m  of  the 
derailing  switch  lever;  the  long  arm  of  the  lever  which 
carries  the  weight  o  is  then  brought  into  the  position  n,  and 
the  switch  rail  or  point  takes  the  position  a  (see  detail  C), 
leaving  the  derailing  switch  open  and  protecting  the  main 
track  from  runaway  cars. 

When,  on  the  other  hand,  the  switch  is  placed  for  the 
siding  E  F,  the  tension  on  the  wire  is  relaxed  and  the  long 
arm  n  of  the  derailing  switch  lever,  being  acted  upon  by  the 


1124 


TRACK  WORK. 


weight  <?,  is  made  to  take  the  position  n' ,  and  the  short  arm 
of  the  lever,  the  position  ;;/'.  This  movement  is  transmitted 
by  the  connection  rod  to  the  switch  rail,  which  takes  the 
position  a'  (see  detail  C),  securely  closing  the  switch.  The 
guard  rail  e  is  secured  to  the  main  rail/  by  two  heavy  bolts, 
the  space  between  them  being  maintained  by  a  cast-iron 
throat  filler  q.  Near  the  derailing  switch,  a  guard  rail  r  is 
placed,  diverging  from  the  outside  rail,  the  object  of  which 
is  to  prevent  derailed  cars  from  running  on  to  the  main  line. 
A  heavy  plank  s  is  spiked  to  the  ties  close  to  the  outside  rail 
to  prevent  any  derailed  trucks  from  turning  up  the  rails. 

1690.     Automatic     Turnouts. — For     dummy     or 
street  car  roads  using  a  light  T  rail,  the  automatic  switch 


Fig.  536. 


shown  in  Fig.  536  may  be  used  on  turnouts,  or  passing 
tracks,  to  great  advantage.  There  are  two  switch  points 
a  and  b,  one  of  which,  a,  is  rigid,  forming  a  combination  of 
frog  and  switch  point.  It  consists  of  a  guard  rail  r,  two 
throat  fillers  d  and  r,  and  the  switch  point  a.  The  throat 
fillers  between  the  switch  point  and  the  head  block  unite, 
forming   a    single    filler,    which    is    grooved  at  f.      When 


TRACK  WORK. 


1125 


approaching  or  leaving  the  switch,  the  wheel  flange  enters  this 
groove,  bringing  the  wheel  tread  safely  upon  the  stock 
rail  g-. 

In  America,  at  least,  it  is  the  universal  custom  for  cars 
approaching  a  passing  track  to  take  the  right-hand  track  in 
the  direction  indicated  in  the  figure  by  the  arrows  m  and  n. 
Accordingly  the  switch  is  always  set  for  the  right-hand 
track,  the  switch  point  d  being  held  firmly  against  the  stock 
rail  /i  by  means  of  the  iron  rod  k,  which  is  acted  upon  by  a 
powerful  spring  confined  in  the  shell  /.  This  shell  is  spiked 
to  the  head  block  between  the  rails,  as  shown  in  the  figure, 
and  hence  is  not  an  obstruction  to  travel,  as  it  would  be  if 
placed  outside  the  rails,  and  it  is  also  comparatively  safe 
from  injury  from  the  wheels  of  heavy  trucks  and  drays. 

A  car  moving  in  the  opposite  direction,  as  indicated  by 
the  arrows,  throws  the  switch  automatically.  As  the  wheel 
flanges  come  in  contact  with  the  switch  rail  d,  the  spiral 
spring  which  holds  the  switch  rail  in  place  yields  to  the 
pressure,  and  the  switch  opens,  allowing  the  car  to  pass 
from  the  siding  to  the  main  track.  The  wheel  flanges,  after 
passing  the  switch  point  a,  enter  the  groove  /,  before  men- 
tioned, and  the  wheel  treads  pass  safely  on  to  the  stock  rail 
g:  As  the  spring  is  constantly  acting,  each  wheel  throws 
the  switch,  which  closes  the  instant  the  wheel  flange  passes 
the  point. 


Pig.  587. 


There  are  three  forms  of  turnouts,  or  passing  tracks,   in 
general  use;  they  are  shown  in   Fig.   537,  at  A,  B,  and  C, 


1126 


TRACK  WORK. 


the  arrows  indicating  the  direction  in  which  cars  enter  and 
leave  the  turnout.  It  will  be  seen  that  some  one  of  these 
three  forms  of  passing  tracks  will  meet  practically  any  given 
situation.  That  shown  at  B  is  particularly  suited  to  track 
laid  along  the  side  of  a  street  or  highway,  which  may  be 
widened  at  the  points  requiring  passing  tracks.  The  form 
shown  at  C  should  always  be  adopted  for  tracks  laid  on  the 
center  line  of  streets.  The  extra  room  required  for  passing 
tracks  is  equally  distributed  on  both  sides  of  the  main  center 
line  of  the  street,  so  that  there  will  be  the  least  possible 
encroachment  upon  the  space  left  for  vehicles, 

1691.     Y  Tracks. — The   form   of    turnout   shown   in 
Fig.   538  is  called   a  Y.     It  is  used   as  a  substitute  for  a 


Fig.  538. 


turntable.  Sometimes  the  switches  are  automatic,  as  shown 
in  the  figure,  in  which  case  all  locomotives  must  enter  the  Y 
from  the  same  end,  viz.,  at  a,  and  leave  at  b.  Usually, 
however,  the  switches  are  operated  by  hand  levers  and  the 
Y  is  entered  from  both  directions.  One  special  advantage 
of  a  Y  track  is  that  both  engine  and  train  may  be  turned 
together,  and  where  favorably  situated,  they  are  much 
used  in  shifting  light  trains  which  are  run  at  frequent  in- 
tervals for  the  accommodation  of  suburban  travel. 


TRACK  WORK. 


1127 


1692.  The  Parts  of  a  Turnout.— The  several  parts 
of  a  turnout  are  represented  in  Fig,  539.  The  distance 
//from  the  P.  C.  of  the 
turnout  curve  to  the 
point  of  frog  is  called 
the  frog  distance. 
The  frog  number  and 
frog  angle  we  have  al- 
ready defined.  The  ra- 
dius c  o  oi  the  turnout 
curve,  the  frog  distance, 
the  frog  angle,  and  the 
frog  number  bear  cer- 
tain relations  to  each 
other,  which  are  ex- 
pressed by  the  following 
formulas :  fig.  S39. 

Tangent  of  half  frog  angle  =  gauge  -t-  frog  distance.    (11 4.) 
Frog  number  =  ^radius  c  o  -^  twice  the  gauge.  (11 5.) 

Frog  number  =  half  the  cotangent  of  half  the  frog  angle. 

(116.) 

Radius  c  o:=  twice  the  gauge  X  square  of  the  frog  number. 

(117.) 

Radius  c  o  =^  {ffog  distance  p  f  -^  sine  of  frog  atiglc)  —  ^  the 
gauge.  (118.) 

Radius  c  o  z=z  gauge  -i-  {1  —  cosine    of   frog    angle')  —  ^   the 
gauge.  (119.) 

Frog  distance  p  f=-  ffog  number  X  tivice  the  gauge.     ( 1 20.) 

Frog  distance  p  f  z=.  gauge  p  q -^  tangent  of  half  the  frog 
attgle.  (121.) 

Frog  distance  p  f  =  {radius  c  o  -\-  half  the  gauge)  X  sine  of 
frog  angle.  (122.) 

Middle  ordinate  {approximate)  =  \  the  gauge.  (123.) 


1128 


TRACK  WORK. 


Each  side  ordinate  {approximate)  =  f  the  middle  ordinate  = 

j%,  (^''  •  188)  of  the  gauge.  (124.) 

Switch  length  approximate  = 


^ 


throw  infeetY.  10,000 


tan  deflection  for  chords  of  100  ft.  for  radius  c  o  of  turnout  cUrve. 

(125.) 

The  tangent  deflection   may  be  obtained  from  the  table 
of  Tangent  and  Chord  Deflections.     • 


TABLE  35. 


TURNOUTS  FROM  A  STRAIGHT  TRACK. 

Gauge,  Jf.  feet  8^  inches.      Throw  of  Switch,  5  inches. 


Frog 

Num- 
ber. 

Frog 
Angle. 

Turnout 
Radius. 

Degree 

of 

Turnout 

Curve. 

Frog 
Dis- 
tance. 

Middle 
Ordi- 
nate. 

Side 
Ordi- 
nate. 

Stub 
Switch 
Length. 

o        / 

Feet. 

o      , 

Feet. 

Feet. 

Feet. 

Feet. 

12 

4  46 

1,356 

4  14 

113.0 

1.177 

.883 

34 

Hi 

4  58 

1,245 

4  36 

108.3 

1.177 

.883 

32 

11 

5  12 

1,139 

5  02 

103.6 

1.177 

.883 

31 

10^ 

5  28 

1,038 

5  31 

98.9 

1.177 

.883 

29 

10 

5  44 

942 

6  05 

94.2 

1.177 

.883 

28 

9i 

6  02 

850 

6  45 

89.5 

1.177 

.883 

27 

9 

6  22 

763 

7  31 

84.7 

1.177 

.883 

25 

8i 

6  44 

680 

8  26 

80.0 

1.177 

.883 

24 

8 

7  10 

603 

9  31 

75.3 

1.177 

.883 

22 

n 

7  38 

530 

10  50 

70.6 

1.177 

.883 

21 

7 

8  10 

•  461 

12  27 

65.9 

1.177 

.883 

20 

6i 

8  48 

398 

14  26 

61.2 

1.177 

.883 

18 

G 

9  32 

339 

16  58 

56.5 

1.177 

.883 

17 

H 

10  24 

285 

20  13 

51.8    1.177 

.883 

15 

5 

1126 

235 

24  32 

47.1    1.177 

.883 

14 

4^ 

12  40 

191 

30  24 

42.4 

1.177 

.883 

13 

4 

14  14 

151 

38  46 

37.7 

1.177 

.883 

11 

TRACK  WORK.  1139 

The  switch  lengths  in  the  above  table  merely  denote  the 
shortest  length  of  stub  sivitch  that  will  at  the  same  time 
form  part  of  the  turnout  curve,  and  give  5  inches  throw. 
Pohit  or  split  sivitchcs  require  a  throw  of  not  more  than  3^ 
inches,  though  many  have  a  throw  of  5  inches,  with  an 
equal  space  between  the  gauge  lines  at  the  heel.  The  heels 
of  a  split  switch,  which  occupy  the  same  position  as  the  toes 
of  a  stub  switch,  should  be  placed  at  the  point  where  the 
tangent  deflection  or  offset  is  5  inches.  The  point  where 
the  tangent  deflection  is  but  4^  inches  will  answer  for  many 
rail  sections,  but  for  those  above  65  lb.  per  yard,  5  inches 
should  be  taken. 

In  the  table  of  Tangent  and  Chord  Deflections,  tangent 
deflections  for  chords  of  100  feet  are  given  for' all  curves  up 
to  20°,  and  for  a  curve  of  higher  degree,  the  tangent  deflec- 
tion may  be  found  by  applying  formula  93,  Art.  1255, 

tan  deflection  =  — ^. 

In  complicated  track  work  where  space  is  limited,  curves 
must  be  chosen  to  meet  the  existing  conditions,  and  not 
with  reference  to  particular  frog  angles,  in  which  case  the 
frogs  are  called  special  frogs,  and  are  made  to  fit  the  par- 
ticular curve  used.  The  determination  of  the  frog  distance, 
switch  length,  and  frog  angle  may  be  understood  by  refer- 
ring to  Fig.  540. 

Let  the  main  track  a  b  he  3.  straight  line;  the  gauge /^  = 
4 feet  Scinches  (==4.71  feet) ;  the  degree  of  the  turnout  curve 
=  13° ;  the  chord  q  d  =  100  feet ;  c  d—  the  tangent  deflection  of 
the  chord  q  d,  and// =  the  frog  distance.  From  the  table 
of  Tangents  and  Chord  Deflections,  we  find  the  tangent  deflec- 
tion for  a  chord  100  feet  long  of  a  13°  curve  is  11.32  feet. 

Then,  from  Fig.  540,  we  have  the  proportion  (see  Art 

1^^^)  cd:  efwYc--  T^- 

Now,  in  curves  of  large  radius  q  c  and  q  d  are  assumed  to 
be  equal.  Also,  q  e^=.p  f,  the  frog  distance,  and  substitu- 
ting these  equivalents,  we  have  the  proportion 

a       . a 

c  d  :  e  f  '.'.  q  d  \  p  f . 


1130 


TRACK  WORK. 


Substituting  the  above  given  quantities  in  the  proportion, 

we  have  ^ 

11.32  :  4.71::  100'  ://; 


whence, 


//  = 


100'  X  4.71 


11.32 
frog  distance  p  f=  64. 5  feet. 


and 


If  the  space  between  the  gauge  lines  of  the  rails  at  the 

heels  of  a  split  switch 
be  taken  at  5  inches  = 
0.42  of  a  foot,  the  dis- 
tance from  the  P.  C. 
of  the  turnout  curve 
to  the  heel  of  the 
switch  may  be  found 
\  as  follows: 

In  Fig.   540,   let   h, 

the  tangent  offset  at 

the  heel  of  the  switch 

=  0.42  of  a  foot,  and 

"^-.  \       we   have   the   propor- 


-----Ij 


FIG.  540. 


tion 
c  d 


h'.'.q  d    '.  q  h  ^ 


and  substituting  known  values,  we  have 
11.32  :  0.42::  100'  :.^/; 


whence, 


qh  = 


«       10,000x0.42 


=.  371.02,  and 


11.32 
qh  =  19.26  feet. 

This  locates  the  heel  of  a  split  switch  and  the  toe  of  a  stub 
switch. 

Th.Q  frog  angle  is  the  angle  k  f  I  (see  Fig.  540)  formed  by 
the  gauge  line  of  the  main  rail  f  k  and  the  tangent  to  the 
outer  rail  q  f  oi  the  turnout  curve  at  the  point  where  the 
two  rails  intersect.  This  angle  is  equal  to  the  central 
angle  q  o  f.  The  arcs  q  /"and  r  s  are  assumed  to  be  of  the 
same  length.     The  turnout  curve  being  13°,   the  central 


TRACK  WORK. 


1131 


1  Q  \/   PC\ 

angle  for  a  chord  of  1  foot  is  —  =  7. 8',  and  the  central 

angle  for  64.5  feet,  the  fro^  distance,  is  7.8'  X  64.5  =  8°  23', 
the  frog  angle  for  a  13°  curve.  By  this  process  the  frog 
distance,  switch  length,  and  frog  angle  may  be  calculated 
for  curves  of  any  radius. 

1693.     To    Lay   Out    a  Turnout  from  a    Curved 
Main  Track. — There  are  two  cases: 

Case  I. — When  the  two  curves  deflect  in  opposite  direc- 
tions, illustrated  by  Fig.  541,  and 

d 


^iO 


Fig.  541. 

Case  II. — When  the  two  curves  deflect  in  the  same  direc- 
tion, illustrated  in  Fig.  542. 

In  Fig.  541,  the  curve  a  d  is  3°  30',  and  it  is  proposed  to 
use  a  No.  8  frog.  By  reference  to  Table  35,  we  find  that 
the  degree  of  curve 
corresponding  to  a  No. 
8  frog  is  9"  31'.  Ac- 
cordingly, we  use  a 
turnout  curve  a  e, 
whose  degree  when 
added  to  the  degree  of 
curve  of  the  main 
track  shall  equal  the 
degree  required  for  a 
No.  8  frog,  i.  e.,  we 
use  a  6"^  turnout  curve, 
which  is  within  one 
minute  of  the  required  fig.  542. 


1132  TRACK  WORK. 

degree,  and  close  enough  for  practical  purposes.  From  our 
knowledge  of  tangent  and  chord  deflections  we  know  that 
for  curves  of  moderate  radii,  i.  e.,  from  1°  up  to  12°,  the 
tangent  deflections  or  offsets  increase  as  the  degree  of  the 
curve.  That  is,  the  tangent  deflection  of  a  2°,  4°,  and 
G°  curve  is  two,  four  and,  six  times,  respectively,  that  of  a 
Incurve.  In  the  accompanying  figures  illustrating  the  loca- 
tion of  frogs  and  switches,  each  curve  is  represented  by  two 
lines  indicating  the  rails,  whereas  only  the  center  lines  of 
the  curves  are  run  in  on  the  ground.  In  Fig.  541,  the  line 
c  d  is  tangent  to  the  center  lines  of  the  curves.  These  center 
lines  do  not  appear  in  the  cut. 

Now,  if,  in  Fig.  541,  a  tangent  c  d  he  drawn  at  c,  the  point 
common  to  the  center  lines  of  the  curves,  the  sum  of  the 
deflections  of  both  curves  from  the  common  tangent  will  be 
equal  to  the  tangent  deflection  of  a  9°  30'  curve  from  a 
straight  line. 

Accordingly,  to  find  the  frog  distance  for  a  6°  turnout 
curve  from  a  3°  30'  'curve,  the  curves  being  in  opposite 
directions,  as  shown  in  Fig.  541,  we  find  the  tangent  deflec- 
tion of  a  9°  30'  curve  for  a  chord  of  100  feet.  This  deflec- 
tion is  8.28  feet  (see  table  of  Radii  and  Deflections).  As- 
suming the  gauge  of  track  to  be  standard,  viz.,  4  ft.^  8^  in.  = 
4.71  ft.,  and  denoting  the  required  frog  distance  by  x,  we 
have  the  following  proportion: 

8.28  :  4.71  ::  100'  :  x"; 

,                       ,      10,000X4.71       ^^oQ  t        A 
whence,  x^  =  — —;^-^ =  5.688.4,  and 

o.  /CO 

frog  distance  x  =  75.42  feet. 

We  use  the  tangent  deflection  for  a  9°  30'  curve,  which  is 
practically  the  same  as  for  a  9°  31'  curve,  and  so  save  the 
labor  of  a  calculation,  which  will  not  appreciably  affect  the 
result. 

We  locate  the  heel  of  the  switch  in  the  same  way,  using 
for  the  second  term  of  the  proportion  0.42  foot,  the  dis- 
tance between  the  gauge  lines  at  the  heel,  instead  of  4.71 
feet,  the  gauge  of  the  track. 


TRACK  WORK.  1133 

In  Fig.  542,  which  comes  under  Case  II,  both  curves  de- 
flect in  the  same  direction,  and  the  rate  of  their  deflection 
from  each  other  is  equal  to  the  rate  of  the  deflection  of  a 
curve  whose  degree  is  equal  to  the  difference  of  the  degrees 
of  the  two  curves  from  a  tangant. 

Let  the  main  track  curve  a  b  he:  5°,  and  the  turnout  curve 
a  c  be  10°.  Then  the  rate  of  deflection  or  divergence  of 
the  10°  curve  from  the  5°  curve  is  equal  to  the  divergence 
of  a  (10°  —  5°)  5°  curve  from  a  straight  track  or  tangent. 

Accordingly,  we  find,  in  the  table  of  Radii  and  Deflections, 
the  tangent  deflection  for  a  5°  curve  for  a  chord  of  100  feet  = 
4.36  feet.  Denoting  the  required  frog  distance  by  x,  we 
have  the  following  proportion : 

4.36  :  4.71::  100' :  jr*; 

whence,  x^  =  ^^'^.^^  ^"^^  =  10,802.8,  and 

4.30 

frog  distance  x  =  103.9  feet. 

Distances  are  not  calculated  nearer  than  to  tenths  of  feet. 

1694.  How  to  Lay  Out  a  Switch. — In  laying  out  a 
switch,  locate  the  frog  so  as  to  cut  the  least  possible  num- 
ber of  rails.  Where  there  is  some  latitude  in  the  choice  of 
location,  the  P.  C.  of  the  turnout  curve  can  be  located,  so 
as  to  bring  the  frog  near  the  end  of  a  rail. 

To  do  this,  take  from  Table  35  the  frog  distance  cor- 
responding to  the  number  of  the  frog  to  be  used.  Locate 
approximately  the  P.  C.  of  the  turnout  curve,  and  measure 
from  it  along  the  main  track  rail  the  tabular  frog  distance. 
If  this  brings  the  frog  point  near  the  end  of  the  rail,  the 
P.  C.  of  the  turnout  curve  may  be  moved  so  as  to  require 
the  cutting  of  dut  one  main  track  rail.  Measure  the  total 
length  of  the  frog  and  deduct  it  from  the  length  of  the  rail 
to  be  cut,  marking  with  red  chalk  on  the  flange  of  the  rail 
the  point  at  which  the  rail  is  to  be  cut.  Measure  the  width 
of  the  frog  at  the  heel  and  calculate  the  distance  from  the 
heel  to  the  theoretical  point  of  frog.  For  example,  if  the 
width  of  the  frog  at  the  heel  is  8^  inches,  and  a  No.  8  frog 


1134  TRACK  WORK. 

is  to  be  used,  the  theoretical  distance  from  the  heel  to  the 
point  Qf  frog  is  8.5x8=08  inches  =  5  feet  8  inches. 
Measure  off  this  distance  from  the  point  marking  the  heel 
of  the  frog.  This  will  locate  the  point  of  frog,  which  should 
be  distinctly  marked  with  red  chalk  on  the  flange  of  the 
rail.  It  is  a  common  practice  to  make  a  distinct  mark  on 
the  web  of  the  main  track  rail,  directly  opposite  to  the  point 
of  frog.  This  point  being  under  the  head  of  the  rail,  it  is 
protected  from  wear  and  the  weather.  The  P.  C.  of  the 
turnout  curve  is  then  located  by  measuring  the  frog  dis- 
tance from  the  point  of  frog.  From  Table  35  we  find  the 
frog  distance  for  a  No.  8  frog  is  75.3  feet,  and  the  switch 
length,  i.  e.,  the  distance  from  the  P.  C.  of  the  turnout 
curve  to  the  heel  of  the  split  switch  or  toe  of  the  stub 
switch,  is  22  feet. 

If  a  stub  switch  is  to  be  laid,  make  a  chalk  mark  on  both 
main  track  rails  on  a  line  marking  the  center  of  the  head 
block.  A  more  permanent  mark  is  made  with  a  center 
punch.  Stretch  a  cord  touching  these  marks,  and  drive  a 
stake  on  each  side  of  the  track,  with  a  tack  in  each.  This 
line  should  be  at  right  angles  to  the  center  line  of  the  track, 
and  the  stakes  should  be  far  enough  from  the  track  as  not 
to  be  disturbed  when  puttmg  in  switch  ties.  Next,  cut  the 
switch  ties  of  proper  length;  draw  the  spikes  from  the  track 
ties,  three  or  four  at  a  time,  and  remove  them  from  the 
track,  replacing  them  with  switch  ties,  and  tamping  them 
securely  in  place.  When  all  the  long  ties  are  bedded,  cut 
the  main  track  rail  for  the  frog,  being  careful  that  the 
amount  cut  off  is  just  equal  to  the  length  of  the  frog.  If, 
by  increasing  or  decreasing  the  length  of  the  lead  5  per 
cent,  you  can  avoid  cutting  a  rail,  do  not  hesitate  to  do  so, 
especially  for  frogs  above  No.  8. 

Use  full  length  rails  (30  feet)  for  moving  or  switch  rails, 
and  be  careful  to  leave  a  joint  of  proper  width  at  the  head 
chair.  Spike  the  head  chairs  to  the  head  block  so  that  the 
main  track  rails  will  be  in  perfect  line.  Spike  from  8  to 
10  feet  of  the  switch  rails  to  the  ties,  and  slide  the  cross 
rods  on  to  the  rail  flanges,  spacing  them  at  equal  intervals. 


TRACK  WORK. 


1135 


The  cross  rods  are  placed  between  the  switch  ties,  which 
should  not  be  more  than  15  inches  from  center  to  center  of 
tie.  The  switch  ties,  especially  those  under  the  moving 
rails,  should  be  of  sawed  oak  timber.  Southern  pine  is  a 
good  second  choice.  Attach  the  connection  rod  to  the  head 
rod  and  to  the  switch  stand.  With  these  connections  made, 
it  is  an  easy  matter  to  place  the  switch  stand  so  as  to  give 
the  proper  throw  of  the  switch. 

It  is  common  practice  to  fasten  the  switch  stand  to  the 
head  block  with  track  spikes,  but  a  better  fastening  is  made 
with  bolts.  The  stand  is  first  properly  placed  and  the  holes 
marked  and  bored,  and  the  bolts  passed  through  from  the 
under  side  of  the  head  block.  This  obviates  all  danger  of 
movement  of  the  switch  stand  in  fastening,  which  is  liable 
to  occur  when  spikes  are  used,  and  insures  a  perfect  throw. 

The  use  of  track  spikes  is  quite  admissible  when  holes  are 
bored  to  receive  them,  in  which  case  a  half-inch  auger 
should  be  used  for  standard  track  spikes.  The  switch  stand 
should,  when  possible,  be  placed  facing  the  switch,  so  as  to 
be  seen  from  the  engineer's  side  of  the  engine — the  right- 
hand  side. 

Next  stretch  a  cord  from  ^,  Fig.  543,  a  point  on  the  outer 
main  track  rail  opposite  the  P.  C.  of  the 
turnout  curve,  to  b^  the  point  of  the  frog. 
This  cord  will  take  the  position  of  the  chord 
of  the  arc  of  the  outer  rail  of  the  turnout 
curve.  Mark  the  middle  point  c  and  the 
quarter  points  d  and  e.  Whatever  the 
degree  of  the  turnout  curve,  the  distance 
from  the  middle  point  c  of  the  chord  to  the 
arc  a  b 'v&  1.18  feet,  and  the  distances  from 
the  quarter  points  d  and  e  are  .88  foot;  al 
hence,  at  c  lay  off  the  ordinate  1.18  feet, 
and  at  both  d^and  e  the  ordinate  .88  foot, 
three-quarters  of  the  middle  ordinate. 
These  offsets  will  mark  the  gauge  line  of 
the  rail  a  b.  Add  to  these  offsets  the  dis- 
tance from  the  gauge  line  to   outside   of  the   rail  flange, 


Fig.  543. 


1136  TRACK  WORK. 

and  mark  the  points  on  the  switch  ties.  Spike  a  lead  rail 
to  these  marks  and  place  the  other  at  easy  track  gauge  from  it. 
Spike  the  rails  of  the  turnout  as  far  as  the  point  of  frog  to 
exact  gauge,  unless  the  gauge  has  been  widened  owing  to 
the  sharpness  of  the  curve.  Beyond  the  point  of  frog  the 
curve  may  be  allowed  to  vary  a  little  in  gauge  to  prevent  a 
kink  showing  opposite  the  frog.  In  case  the  gauge  is 
widened  at  the  frog,  increase  the  guard  rail  distance  an 
equal  amount.  For  a  gauge  of  4  feet  8^  inches,  place  the 
side  of  the  guard  rail  which  comes  in  contact  with  the  car 
wheels  at  4  feet  G|  inches  from  the  gauge  line  of  the  frog. 
This  gives  a  space  of  1|-  inches  between  the  main  rail  and 
the  guard  rail. 

In  case  the  gauge  is  widened  :^  or  ^  inch,  increase  the 
guard  rail  distance  an  equal  amount. 

When  the  turnout  curve  is  very  sharp,  it  will  be  neces- 
sary to  curve  the  switch  rails,  to  avoid  an  angle  at  the 
head  block.  The  lead  rails  should  be  carefully  curved  be- 
fore being  laid,  and  great  pains  taken  to  secure  a  perfect 
line. 

If  2i  point,  or  split,  switch  is  to  be  laid,  the  order  of  work 
is  nearly  the  same.  The  same  precautions  must  be  taken  to 
avoid  the  unnecessary  cutting  of  rails,  with  the  additional 
precaution  of  keeping  the  switch  points  clear  of  rail  joints, 
as  the  bolts  and  angle  splices  will  prevent  the  switch  points 
from  lying  close  to  the  stock  rails.  As  already  stated, 
these  conditions  can  usually  be  met  where  there  is  some 
range  in  the  choice  of  the  location  of  the  switch.  Where 
there  is  none,  the  main  track  rails  must  be  cut  to  fit  the 
switch. 

Having  located  the  point  of  frog,  the  P.  C.  of  the  turnout 
curve,  and  the  heel  line  of  the  switch,  measure  back  from  the 
heel  line  a  distance  equal  to  the  length  of  the  switch  rails, 
and  place  on  the  flange  of  each  rail  a  chalk  mark  to  locate 
the  ends  of  the  switch  points.  This  will  also  locate  the  head 
block.  Prepare  switch  ties,  of  the  requisite  number  and 
length,  and  place  them  in  the  track  in  proper  order.     As  in 


TRACK  WORK.  1137 

the  case  of  stub  switches,  see  to  it  that  all  long  switch  ties 
are  in  place  before  cutting  the  rail  for  placing  the  frog; 
also,  that  the  ends  of  the  lead  rails,  with  which  the  switch 
points  connect,  are  exactly  even ;  otherwise  the  switch  rods 
will  be  skewed,  and  the  switch  will  not  work  or  fit  well. 
Fasten  the  switch  rodsjn  place,  being  careful  to  place  them 
in  their  proper  order,  the  head  rod  being  No.  1.  Each  rod 
is  marked  with  a  center  punch,  the  number  of  the  punch 
marks  corresponding  to  the  number  of  the  rod. 

Couple  the  switch  points  with  the  lead  rails  and  place  the 
sliding  plates  in  position,  securely  spiking  them  to  the  ties. 
Connect  the  head  rod  with  the  switch  stand,  and  close  the 
switch,  giving  a  clear  main  track. 

Adjust  the  stand  for  this  position  of  the  switch,  and  bolt 
it  fast  to  the  head  block.  Next,  crowd  the  stock  rail  against 
the  switch  point  so  as  to  insure  a  close  fit,  and  secure  it  in 
place  with  a  rail  brace  at  each  tie;  then  continue  the  laying 
of  the  rails  of  the  turnout. 

If  there  is  no  engineer  to  lay  out  the  center  line  of  the 
turnout,  the  section  foreman  can  put  in  the  lead  from  or- 
dinates,  as  explained  in  Fig.  543.  In  modern  railroad  prac- 
tice, however,  most  track  work  is  done  under  the  direction 
of  an  engineer,  in  which  case  the  center  line  of  the  turnout 
is  located  with  a  transit.  This  ensures  a  correct  line  and  ex- 
pedites work.  For  ordinary  curves,  center  stakes  at  inter- 
vals of  50  feet  are  sufficient,  excepting  between  the  P.  C.  of 
the  turnout  and  the  point  of  frog,  where  there  should  be  a 
center  stake  at  each  interval  of  25  feet.  Place  a  guard  rail 
opposite  the  point  of  frog  on  both  main  track  and  turnout. 
The  guard  rail  should  be  10  feet  in  length;  this  is  an 
economical  length  for  cutting  rails,  as  each  full-length  rail 
makes  three  guard  rails. 

Two  styles  of  guard  rails  are  shown  in  Fig.  544.  That 
shown  at  B  is  in  general  use,  but  the  style  shown  at  A  is 
growing  in  favor. 

The  latter  is  curved  throughout  its  entire  length.  At  its 
middle   point  a^  directly  opposite   the   point   of   frog,  the 


1138 


TRACK  WORK. 


guard  rail  is  spaced  1|-  inches  from  the  gauge  line  of  the 
turnout  rail  b  c.  From  this  point  the  guard  rail  diverges  in 
both  directions,  giving  at  each  end  a  flange-way  of  4  inches. 
This  allows  the  wheels  full  play,  excepting  at  the  point  of 
frog,  where  the  guard  rail  is  exactly 
adjusted  to  the  track  gauge,  and  holds 
the  wheels  in  true  line,  preventing  them 
from  climbing  or  mounting  the  frog. 
The  style  of  guard  rail  shown  at  B^ 
though  still  much  used,  has  two  ob- 
jectionable features,  viz.,  first,  the 
abruptly  curved  ends  d  and  e  often  re- 
ceive an  almost  direct  blow  from  the 
wheel  flanges,  which  causes  a  car  to 
lurch  violently;  and  second,  the  flangCr 
way  of  uniform  width,  though  proper 
for  the  main  track  when  straight,  as 
in  Fig.  544,  is  unsuited  for  sharp  curves 
on  either  a  main  track  or  a  turnout,  as 
it  compels  the  wheels  to  follow  a  curved 
line;  whereas,  the  normal  position  of 
the  wheel  base  of  each  truck  is  that  of  a  chord  of,  or  a  tan- 
gent to,  the  curve.  These  two  defects  alone  produce  what 
is  known  as  a  rough-riding  frog,  even  though  the  frog  is 
well  lined  and  ballasted. 

It  is  customary  to  bend  the  stock  rail  with  a  rail  bender  in 
the  proportion  of  about  1  to  40,  placing  the  angle  about  10 
inches  back  from  the  switch  points,  so  that  the  beveled 
points  will  lie  snugly  against  the  stock  rail.  Exception  to 
this  rule  is  found  in  the  practice  of  the  Philadelphia  and 
Reading  R.  R.,  where  the  switch  points  are  curved  so  as  to 
fit  the  stock  rail,  which  is  not  bent  at  the  switch  point,  but 
laid  to  an  exact  curve. 

The  custom  of  half  spiking  side  tracks  should  be  con- 
demned as  unsafe  and  very  poor  economy.  Side  tracks 
should  receive  as  thorough  work  as  the  main  line,  though,  of 
course,  they  require  less  of  it.  This  point  has  been  touched 
upon  before. 


Pig.  644. 


TRACK  WORK.  1139 

1695.  Laying  Frogs  in  Track. — In  placing  a  frog 
in  the  track,  special  care  should  be  taken  to  put  it  in  perfect 
line  and  surface  with  the  rails  with  which  it  connects. 
Couple  the  frog  to  the  main  track  rails  and  put  them  in  perfect 
line  before  spiking.  This  is  more  certain  to  give  a  true  line 
to  the  frog  than  to  spike  the  connecting  rails  before  coupling 
with  the  frog.  If  the  main  track  is  in  poor  line,  put  in  track 
centers  for  lining  the  frog,  for  it  is  very  difficult  to  correct 
defects  in  line  after  a  switch  is  once  in  place.  Having  spiked 
the  frog  in  place,  put  the  rail  opposite  the  frog  in  perfect 
gauge  for  the  full  length  of  the  frog,  if  on  a  tangent,  and  at 
the  point  of  frog,  if  on  a  curve.  To  have  a  frog  in  perfect 
gauge,  try  the  gauge  at  each  end  of  the  frog,  and  at  about 
six  inches  back  of  the  frog  point. 

If  the  curve  is  very  sharp  and  laid  to  a  uniform  gauge 
throughout,  an  ugly  kink  is  left  opposite  the  frog.  This 
defect  is  caused  by  the  frog  rail,  which  is  necessarily  straight, 
and  can  be  remedied  by  spiking  the  rail  to  gauge  ojily 
at  the  point  of  frog,  and  allowing  it  to  assume  its  natural 
curve  for  the  remainder  of  the  frog's  length. 

Turnout  curves  of  long  radii  require  long  frogs,  and  the 
track  can  be  spiked  to  proper  gauge  throughout  its  length 
without  any  perceptible  kink  at  the  frog. 

Long  frogs  and  long  leads  are  the  best  where  it  is  practi- 
cable to  use  them.  The  wear  from  sharp  curves  and  short 
frogs,  both  upon  rails  and  rolling  stock,  is  great,  and 
they  are  to  be  used  only  where  limited  space  requires 
them. 

1696.  Switch  Timbers. — Every  first-class  railroad 
has  its  own  standards  for  switches,  which  include  the  neces- 
sary switch  timbers.  The  following  rule  will  answer  well 
for  general  use: 

Rule. —  To  find  the  number  of  tics  required  for  any  switch 
lead,  reduce  to  inches  the  distance  from  the  head-block  to  the 
last  long  tic  behind  the  frdg,  and  divide  this  distance  by  the 
number  of  inches  from  center  to  center  of  tie;  the  quotient 
ivill  be  the  number  of  ties  required. 


1140  TRACK  WORK. 

Example. — The  distance  from  the  head  block  to  the  last  tie  behind 
the  frog  is  77  feet.  The  ties  are  spaced  21  inches  center  to  center. 
What  is  the  number  of  ties  required  for  the  switch  ? 

Solution.— 77  feet  =  924  inches;  924  h- 21  =  44,  the  number  of  ties 
required.     Ans. 

Switch  ties  should  be  10  inches  in  width  and  at  least  G 
inches  in  thickness,  though  7  inches  is  preferable.  The 
head-block  should  be  12  inches  in  width  and  8  inches  in 
thickness,  and  16  feet  in  length.  When  timber  may  be 
furnished  in  odd  lengths,  the  following  list  will  furnish  the 
necessary  timber  for  a  given  switch,  which  is  a  single  throw, 
and  requiring  a  No.  8  frog: 

SWITCH   TIES   21    INCHES   TO  CENTER. 

1  head-block  8"  X  12"  X  16'  long. 

8  pieces  6"  X  10"  X    9'  long. 

8  pieces  6"  X  10"  X  10'  long. 

8  pieces  6"  X  10"  X  11'  long. 

5  pieces  6"  X  10"  X  12'  long. 

5  pieces  6"  X  10"  X  13'  long. 

5  pieces  6"  X  10"  X  14'  long. 

3  pieces  6"  X  10"  X  15'  long. 

When  even  lengths  only  can  be  ordered,  the  list  must  be 
modified,  only  care  must  be  taken  to  have  the  timber  long 
enough. 

Switch  ties  in  important  yards  should  not  be  more  than  9 
inches  apart,  if  they  are  to  be  kept  in  proper  surface.  It  is 
poor  economy  to  use  inferior  timber  for  switch  ties,  or  a  scant 
number  of  ties.  Switch  building  is  expensive  work,  and 
should  be  made  as  permanent  as  is  practicable. 

To  cut  switch  ties  the  proper  length  apply  the  following 
rule: 

Rule. — Measure  the  length  of  the  tie  next  the  head  block 
and  the  length  of  the  last  long  tie  behind  the  frog.  Find  the 
difference  in  inches  betiveen  them.  Divide  this  difference  by 
the  number  of  ties  in  the  sioiteh  lead ;  the  quotient  i^'ill  be  the 
increase  in  length  per  tie  from  the  head  block  towards  the  frog 


TRACK  WORK.  1141 

to  have  the  ends  of  the  ties  in  proper  line  on  both  sides  of  the 
track. 

Example. — The  length  of  the  tie  next  the  head  block  is 
8  feet  6  inches  =  102  inches.  The  length  of  the  last  tie 
behind  the  frog  is  15  feet  =  180  inches.  The  difference 
between  the  lengths  of  the  ties,  180  —  102  =  78  inches, 
which,  divided  by  44,  the  required  number  of  ties,  gives  1.8, 
say  If  inches,  the  average  increase  in  length  per  tie. 

There  is  nothing  gained  by  giving  to  switch  ties  a  greater 
projection  outside  the  rails  than  ordinary  track  ties.  They 
add  to  the  labor  of  raising  the  track,  are  unsightly,  and 
labor  is  wasted  in  tamping  up  the  long  ends.  The  switch 
ties  should  be  cut  to  proper  length,  marked  with  chalk  in 
consecutive  numbers,  and  a  mark  for  the  outside  flange  of 
the  main  track  rail  placed  on  each  tie  for  lining  them.  Any 
one  acquainted  with  track  work  knows  that  the  labor 
of  cutting  ties  to  exact  length,  numbering  them,  and  mark- 
ing them  for  proper  lining  is  labor  saved.  There  is  then 
no  time  wasted  in  cutting  and  trying;  the  work  can  be 
pushed  from  start  to  finish,  and  the  result  is  a  perfect  piece 
of  work. 

1697.  Tamping  Switch  Ties. — Before  tamping  up 
a  set  of  switch  ties,  raise  the  track  to  a  uniform  surface. 
Tamp  the  ties  under  the  frog  and  main  track  rail  first,  rais- 
ing the  frog  a  shade  higher  than  the  rest  of  the  switch. 
The  head  block  should  also  be  about  one-quarter  of  an  inch 
above  the  common  surface,  especially  if  a  stub  switch,  as 
the  continual  jarring  caused  by  wheels  passing  the  open 
joint  will  cause  the  head  block  to  settle  slightly.  Tamp  up 
the  middle  of  the  ties  first  and  then  the  outer  ends.  This 
will  prevent  any  sagging  of  the  ties  at  center  and  a  corre- 
sponding rise  at  the  ends.  If  possible,  complete  the  tamp- 
ing before  a  train  passes  the  switch. 

1698.  Three-Throw      Switch      Timbers.  —  The 

lengths  of  switch  timbers  for  a  three-throw  switch  are  found 
by  doubling  the  lengths  of  those  for  a  single  turnout,  and 
subtracting  from  each  the  length  of  the  standard  cross-tie, 


1142 


TRACK  WORK. 


Before  placing  them  in  the  switch,  draw  a  chalk  line  across 
the  middle  of  each  tie,  and  number  them  in  the  same  order 
as  in  a  single  turnout.  Then,  place  them  under  the  main 
track  rail,  and  make  the  middle  mark  of  each  switch  tie 
coincide  with  the  middle  point  of  the  track  gauge  placed  on 
the  main  track  above  the  tie. 

1 699.  Location  of  Crotch  Frog. — A  crotch,  or  mid- 
dle, frog  is  a  frog  placed  at  the  point  where  the  outer  rails 
of  both  turnouts  of  a  three-throw  switch  cross  each  other. 
When  both  turnouts  are  of  the  same  degree,  the  crotch  frog 
comes  midway  between  the  main  track  rails.  Its  location 
and  angle  may  be  determined  as  follows :  Let  the  turnout 
curves  A  and  B,  Fig,  545,  be  each  9°  30',  uniting  with  the 


Fig.  545. 

main  track  C  by  a  three-throw  switch.     Let  a  be  the  P.  C. 

common  to  both  curves,  and  d,  the  location  of   the  crotch  or 

middle  frog. 

It  is  evident  that  the  point  of  the  crotch   frog  should  be 

exactly  midway  between  the  gauge  lines  of  the  main  track 

rails,  and  if  the  gauge  is  4  feet  8^  inches  =  4.71  feet,  the 

4  71 
pomt  of  the  crotch  frog  will  be  — -— =  2.35  feet  from  each 

rail.  Now,  the  problem  is  to  find  the  frog  distance  from  a, 
the  P.  C,  to  the  point  c,  where  the  tangent  deflection  will 
equal  2.35,  or  half  the  gauge.  From  the  table  of  Radii  and 
Deflections,  we  find  the  tangent  deflection  of  a  9°  30'  curve 
is  8.28  feet.     Applying  the  principle  explained  in  Art.  1692 


TRACK  WORK.  1143 

and  Fig.  540,  and  letting  x  represent  the  required  frog  dis- 
tance, we  have  the  following  proportion: 

8.28  :  2.35::  100'  :;r'; 

whence,  x""  =  l^^l^Al^  =  2,838.2  feet, 

8.  Zo 

and  X  =  53.3  feet,  nearly, 

the  required  frog  distance. 

Now,  there  are  two  curves  starting  at  the  common  point  a ; 

the  outer  rails  intersect  at  If,. and  the  angle  d  b  c,  formed  by 

tangents  drawn  to  the  point  of  intersection,  is  the  angle  of 

the  crotch  or  middle  frog.     The  angle  is  equal  to  the  sum 

of  the  angles  a  f  b  and  a  f  b\  that  is,  equal  to  double  the 

central  angle  of  either  curve  between  the  P.  C.  and  the  point 

of  intersection  b.     The  degree  of  the  curve  is  9"  30'  =  5?0', 

570' 
and  the  central  angle  or  total  deflection  for  each  foot  is  -—  = 

5.7',  and  for  the  frog  distance  of  53.3  feet,  the  central 
angle  is  53.3  X  5.7  =  303.8' =  5"*  03.8'.  The  angle  of  the 
crotch  frog  is  double  this  angle,  i.  e.,  5°  03.8'  X  2=  10° 
07.  G'.  The  crotch  frog  should  be  accurately  located  and 
spiked  in  place  before  the  lead  rails  are  placed. 

The  one  objection  to  the  three-throw  switch  is  the  open 
joint  at  the  head  block,  the  inevitable  attendant  of  the  stub 
switch,  but  its  advantages  are  so  great  that  it  will  continue 
to  be  used,  especially  in  yard  service. 

1  700.  Cross-Over  Tracks. — A  cross-over  is  a  track 
by  means  of  which  a  train  passes  from  one  track  to  another. 
The  tracks  united  are  usually  parallel,  as  are  the  tracks  of 
a  double  track  road.  Such  a  cross-over  is  shown  in  Fig. 
540.  The  tracks  a  b  and  c  d  are  13  feet  apart  from  center  to 
center,  which  is  the  standard  distance  for  double  tracks. 
The  cross-over  consists  of  two  turnout  curves,  e  f  and  ^  h. 
These  curves  are  usually,  though  not  necessarily,  of  the 
same,  degree.  The  curve  terminates  at  the  points  of  frog/" 
and  //,  between  which  the  track  f  h  is  a  tangent.  The 
essential  point  in  laying  out  a  cross-over  is  to  so  place  the 


1144  TRACK  WORK. 

frogs  that  the  connecting  track  shall  be  tangent  to  both 
cu^'ves.  In  Fig.  546,  suppose  the  frogs  are  No.  9,  requiring 
7°  31'  turnout  curves. 

From  Table  35,  we  find  the  required  frog  distance  is 
84.7  feet,  and  the  switch  length  25  feet.  As  previously 
noted,  if  there  is  considerable  range  in  choice  of  location, 
the  frogs  can  be  so  placed  as  to  largely  avoid  the  cutting  of 
rails;  but  usually  cross-overs  are  required  at  certain  precise 
places,  and  the  rails  must  be  cut  as  occasion  demands. 
Having  located  the  point  of  frog  at  /,  we  determine  the 
point  of  the  next  frog  at  /z,  as  follows:     A  No.  9  frog  is  one 


Fig.  546. 

which  spreads  1  inch  in  width  to  every  9  inches  in  length, 
and  as  the  track  between  the  frog  points  is  straight,  the 
distance  /  Jl  between  these  points  will  be  as  many  times 
9  inches  as  is  the  space  k  between  the  tracks  at  the  frog  point 
f.  The  main  track  centers  are  13  feet  apart,  making  the 
space  between  the  gauge  lines  of  the  inside  rails  8  feet 
3^'  inches.  As  it  is  the  rail  /  of  the  turnout  which  joins  the 
second  frog  at  h,  we  subtract  the  gauge,  4  feet  8^  inches, 
from  8  feet  3^  inches,  leaving  3  feet  7  inches,  the  distance  k, 
between  the  gauge  line  of  the  rail  /,  opposite  the  frog  point 
y,  and  the  gauge  line  of  the  nearest  rail  of  the  track  c  d. 
This  distance  multiplied  by  9  inches  will  give  the  distance 
from  the  frog  point  f  to  the  frog  point  // ;  3  feet  7  inches 
=  43  inches,  43  X  9  =  387  inches  =  32  feet  3  inches.  Ac- 
cordingly having  located  the  point  of  frog  /",  we  mark  a 
corresponding  point  on  the  nearest  rail  of  the  opposite  track. 
From  this  point  we  measure  along  the  rail  the  distance  32 
feet  3  inches,  locating  the  second  frog  point  //,  and  again  the 
frog  distance  84.7  feet  to  the  P.  C.  of  the  second  turnout 
curve  at  g. 

If  frogs   of  different   numbers,    say    7   and   9,    were   to 


Mr. 


r 


TRACK  WORK.  1145 

be  used,  the  distance  between  the  frogs  is  found  as  fol- 
lows: 

As  the  No.  7  frog  spreads  1  inch  in  7  inches,  and  the  No.  9 
frog  1  inch  in  9  inches,  the  two  will  together  spread  2  inches 
in  7  +  9  =  16  inches,  or  1  inch  in  8  inches.  Now,  if  the  rails 
to  be  united  are  3  feet  7  inches,  or  43  inches  apart,  as  in  the 
previous  problem,  the  distance  between  the  frog  points  will 
be  43  X  8  =  344  inches  =  28  feet  8  inches. 

In  locating  cross-over  tracks,  regard  should  be  paid 
to  the  direction  in  which  the  bulk  of  the  traffic  moves, 
and  the  cross-over  tracks  should  be  so  placed  that  loaded 
cars  will  be  backed,  not  pushed,  from  one  track  to  the 
other. 

At  all  stations  on  double  track  roads  there  should  be  a 
cross-over  to  facilitate  the  exchange  of  cars  and  the  making 
up  of  trains. 

YARDS    AND    TERMINALS. 

1701.  This  subject  includes  the  laying  out  and  main- 
tenance of  the  extensive  railway  yards  which  are  found  at 
all  terminal  and  division  points. 

A  terminal  to  be  effective  must  provide  ample  track  room 
for  all  cars  being  stored,  unloaded,  or  exchanged,  with  the 
tracks  so  arranged  that  terminal  business  may  be  transacted 
with  facility  and  dispatch.  To  save  time  is  to  save  money 
in  all  departments  of  a  railroad.  Much  time  is  unavoidably 
consumed  in  transferring  cars  to  foreign  lines,  making  up 
trains,  and  shifting  cars  to  freight  depots  or  side  tracks  for 
unloading;  but  a  badly  arranged  yard  involves  waste  of 
time  and  increased  forces  of  men  and  engines.  Hence,  the 
laying  out  of  yards  and  terminals  should  be  placed  in  the 
hands  of  men  of  judgment  and  large  experience.  Further- 
more, a  railroad  company  can  well  afford  to  incur  large 
expenditure  in  first  cost  if  they  thereby  avoid  the  con- 
tinual extra  expense  due  to  badly  arranged  yards  and 
terminals. 

A  well-arranged  terminal  is  shown  in  Fig.  547,  in  which 
practically  all  the  requirements  for  local  and  through  traffic 


1146  TRACK  WORK. 

and  for  traffic  exchange,  both  by  rail  and  water,  are  fully 
met. 

The  railroad  has  a  double  track,  a  a'  and  b  b' .  The 
passenger  station  A  is  placed  where  two  important  streets 
intersect,  and  should  be  as  near  the  center  of  population 
and  business  as  is  practicable.  This  station  combines  two 
buildings,  the  one  c  in  front,  containing  the  passenger, 
baggage,  and  express  rooms  on  the  first  floor  and  the  general 
offices  of  the  company  on  the  upper  floors.  The  rear  build- 
ing rtT  is  a  train  shed,  and  contains  six  tracks,  with  platforms 
between.  These  platforms  should  be  from  8  to  10  feet  in 
width,  so  that  passengers  need  not  crowd  each  other  while 
taking  the  cars.  In  many  of  the  best  stations,  these  plat- 
forms are  of  concrete,  finished  smooth  with  Portland  cement. 
This  makes  an  excellent  walk,  is  fireproof  and  enduring. 
The  roof  should  be  of  iron,  and  the  entire  station  made 
fireproof,  if  practicable. 

Empty  passenger  coaches  are  stored  on  the  tracks  ^,  con- 
venient to  the  station.  The  freight  station  and  offices  are 
shown  at  B.  This  station  is  in  four  parts.  The  first  part 
y,  in  front,  contains  the  freight  offices,  and  is  usually  two  or 
three  stories  in  height.  The  parts  g  and  //  are  freight 
rooms  for  receiving  and  discharging  freight.  The  part  k  is 
a  train  shed,  containing  six  tracks,  allowing  three  rows  or 
banks  of  cars  for  each  freight  room.  The  cars  are  backed 
into  the  train  shed  with  the  car  doors  on  each  track  on  line 
with  those  on  the  adjoining  tracks.  Bridges  of  either  planks 
.  or  sheet  iron  extend  from  car  door  to  car  door,  so  that  two 
or  three  rows  of  cars  may  be  loaded  at  the  same  time.  By 
this  means  a  way  freight  train  for  a  long  line  with  numer- 
ous stations  may  be  loaded  with  dispatch  and  without 
confusion. 

The  freight  rooms  have  no  outside  platforms.  Drays 
loaded  with  outgoing  freight  back  up  to  the  doors  of  the 
freight  room;  the  freight  is  discharged  directly  into  the 
freight  room,  and  often  is  carried  by  trucks  directly  from 
the  drays  to  the  car.  This  saves  the  delay  and  expense  of 
rehandling,   which   would    result    from    discharging    from 


'Track  work.  lut 

drays  to  a  platform.  Trains  of  local  freight  are  stored  on 
the  tracks  /  while  awaiting  their  turn  for  unloading,  and 
cars  laden  with  outgoing-  freight  may  be  stored  on  the 
tracks  in  until  a  train  is  made  up. 

It  will  be  observed  that  the  main  tracks  a  a!  and  b  b'  are 
comparatively  free  from  switches,  excepting  at  the  pas- 
senger train  yard  and  station.  All  tracks  entering  the 
passenger  station  A  connect  with  the  outbound  track  b  b' . 
All  the  tracks  connecting  with  the  freight  station  B  are 
thrown  from  the  main  stem  track  ;/,  which  connects  with 
the  outbound  main  track  b  b' .  The  streets  o  and/,  adjoin- 
ing the  freight  station,  are  extended  to  accommodate  drays 
or  other  vehicles  while  unloading  freight  in  car  lots  from 
the  adjoming  sidings. 

The  track  ^  r  is  sometimes  called  a  ladder  track.  It  runs 
diagonally  across  the  yard,  intersecting  all  tracks  and  con- 
necting with  each  by  means  of  slip  switches,  shown  in  detail 
at  A'  and  B' .  This  track  extends  to  the  steamship  wharves 
C  and  D.  Two  tracks  run  alongside  each  pier,  the  tracks 
being  depressed  so  as  to  bring  the  car  floors  nearly  on  a 
level  with  the  deck  of  the  pier.  The  passenger  room  and 
steamship  offices  are  at  E.  Additional  side  tracks  for  local 
freight  in  car  lots  are  shown  at  s  and  /.  Additional  rail- 
road wharves  are  shown  at  F,  G,  and  H.  Wharves  should 
be  covered  with  strong  sheds,  and  when  the  pier  foundation 
is  of  stone  or  creosoted  piles,  it  is  economy  to  build  the  shed 
of  iron.  Grain  elevators  are  shown  at  /  and  K.  The 
tracks,  five  in  number,  run  between  the  elevators,  giving 
abundant  dockage  for  ships  on  either  side. 

The  wharves  Z,  M,  N,  O,  P,  and  Q  are  for  coal  traffic. 
The  piers  support  coal  pockets,  which  have  sufficient  eleva- 
tion to  cause  the  coal  to  run  by  gravity  into  the  holds  of 
vessels  lying  alongside.  The  track  v,  connecting  with  the 
main  track  b  b\  has  an  ascending  grade  not  to  exceed  2  per 
cent.,  which  gives  sufficient  elevation  to  the  spur  tracks 
running  on  to  the  coal  wharves. 

Track  x^  connecting  with  the  elevated  track  v,  leads  to  a 
coal   chute  R.     The  buildings  shown  at  S,  T,  and    U  are 


1148  TRACK  WORK. 

warehouses,  where  freight  is  stored  in  bond  or  otherwise 
for  future  deHvery.  A  foundry  is  represented  by  J\  a  car 
shop  by  IV,  a  machine  shop  by  A',  a  roun'd  house  with  turn- 
table by  V,  and  a  chute  for  coaling  engines  by  Z.  The 
engine  and  boiler  house  j  is  so  situated  that  it  can  supply 
steam  to  foundry,  car,  and  machine  shops.  Track  r,  as  well 
as  (/ r,  is  a  ladder  track.  The  tracks  C  are  for  outgoing 
trains  and  for  cars  to  be  transferred  to  foreign  lines. 
Tracks  D'  are  for  storing  local  and  steamship  freight. 
Tracks  approach  the  turntable  at  V  from  both  directions, 
which  saves  time  and  switching.  Cross-overs  are  placed  at 
the  points  where  there  is  frequent  shifting  of  cars  from  one 
track  to  another.  The  slip  switches,  shown  at  A'  and  /?'  in 
detail  A,  combine  economy  of  space  with  great  flexibility 
and  greatly  simplify  the  work  of  shifting  cars  and  making 
up  trains. 


GENERAL  INSTRUCTIOXS. 

1702.  Inspecting  a  Section  from  a  Car  or 
Engine. — Section  foremen  should  occasionally  ride  over 
their  section  either  on  an  engine,  a  caboose,  or  the  rear  car 
of  a  passenger  train,  and  note  carefully  the  action  of  the 
car  while  passing  over  the  track.  A  defect  in  line  or  sur- 
face, which  would  scarcely  have  any  effect  upon  a  car  run- 
ning 20  miles  an  hour,  would  cause  one  running  at  a  speed 
of  45  miles  an  hour  to  lurch  violently.  This  is  owing  to 
the  fact  that  a  speed  of  20  miles  an  hour  will  permit  a  car 
to  become  righted  after  passing  one  defect  before  coming  to 
a  second,  while  a  car  running  at  a  speed  of  45  miles  an 
hour  may  encounter  several  defects  in  line  or  surface  in  a 
second  of  time. 

If  a  car  lurches  badly  when  passing  over  a  straight  line, 
the  track  at  that  spot  is  either  low  or  badly  out  of  gauge. 
If,  in  passing  over  a  curve,  the  car  swings  to  the  outside  of 
the  curve,  there  is  not  sufficient  elevation  to  the  outer  rail, 
but  if  the  car  swings  towards  the  inside  of  the  curve,  there 
is  too  much  elevation  in  the  outer  rail  at  that  place. 


TRACK  WORK.  1149 

An  observing,  alert  man  will  soon  become  expert  in 
detecting  the  different  movements  of  the  c^r  as  it  swings 
to  either  side  of  the  track,  and  should  determine  the  cause 
by  walking  over  the  track  immediately  after  riding  over  it, 
and  remedy  the  defects  in  the  track. 

1 703.  Avoid  Attaching  Hand  or  Pusb  Cars  to 
Trains. — Foremen  should  never  attach  a  hand  or  push  car 
to  a  train  to  avoid  the  labor  of  pumping  or  pushing  the  car 
to  its  destination.  Many  serious  accidents  have  resulted 
from  such  action.  The  sudden  slackening  or  stopping  of  a 
train  is  likely  to  throw  the  hand  or  push  car  under  the  train 
in  spite  of  every  effort  to  prevent  it,  and  serious  injury,  if 
not  death,  is  the  sure  result. 

1704.  Al^vays  Carry  a  Track  JTack. — Foremen 
should  never  be  out  on  their  sections  without  a  track  jack. 
Keep  it  on  the  hand  car  when  not  in  use,  so  it  will  always  be 
available.  In  no  way  is  time  oftener  wasted  than  in 
attempting  to  raise  a  rail  with  a  makeshift  lever  when  the 
track  jack  has  been  left  behind  at  the  section  house.  Fre- 
quently, the  spikes  are  drawn  from  the  ties  and  the  track 
marred  both  in  gauge  and  surface  by  it. 

The  track  jack  is  one  of  the  best  and  most  economical 
tools  in  use  upon  a  railroad,  and  every  section  should 
possess  one  and  make  the  utmost  use  of  it. 

1 705.  The  Track  Level. — Always  carry  a  track  level 
when  going  out  on  the  section  to  pick  up  or  surface  track. 
It  is  useless  to  attempt  to  surface  track  without  a  spirit 
level,  though  low  spots  in  a  track  which  has  once  been  put 
in  good  surface  may  be  put  in  proper  surface  by  sighting. 

1  706.  Rails  of  Different  Heights.— Where  rails  of 
different  heights  meet  at  a  joint,  they  should  be  connected 
by  a  step  splice,  and  an  iron  shim  should  be  placed  under  the 
low  rail,  to  bring  the  tops  of  both  rails  to  the  same  level. 
The  shim  should  be  slotted  at  the  sides,  and  spikes  driven 
through  the  slots,  to  hold  the  shim  in  place. 


iloO  TRACK  WORK. 

1707.  Extra  Men. — When  a  section  foreman  is  about 
to  largely  increase  his  force  for  temporary  work,  he  should 
take  time  to  carefully  plan  his  work  and  the  disposition  of 
his  men.     Work  well  organized  is  half  done. 

1708.  Getting  Acquainted  with  tlie  Section.— 

Every  section  foreman  should,  immediately  upon  taking 
charge  of  his  section,  thoroughly  acquaint  himself  with 
everything  connected  with  it  and  his  work.  He  should 
know  the  length  of  his  section,  the  location  and  degree  of 
each  curve,  the  number  and  location  of  each  bridge,  trestle, 
cattle  guard,  crossing,  and  culvert,  the  weight,  brand,  and 
age  of  all  steel  and  its  location,  the  number  of  panels  of 
snow  fence,  the  height  of  bridges  from  the  ground,  the  loca- 
tion of  whistling  posts,  the  numbers  of  all  frogs,  and  any 
information  which  can  assist  a  foreman  in  making  out 
correct  and  prompt  reports  to  the  roadmaster. 

1709.  Drilling  Rails. — When  it  is  necessary  to  cut 
rails  in  putting  in  switches,  or  in  repairing  track,  the  rails 
should  be  full  drilled  and  bolted  at  every  joint.  A  joint  but 
half  bolted  is  sure  to  sag  in  a  short  space  of  time. 

1710.  Lining  Disconnected  Track. — When  lining 
disconnected  track  that  has  been  washed  out,  always  com- 
mence at  the  connected  end,  else  it  will  be  practically 
impossible  to  get  the  track  in  line. 

1711.  Cutting  Steel. — Section  foremen  should  care- 
fully instruct  their  men  how  to  cut  rails.  The  cut  of  the 
chisel  should  be  a  continuous  line  extending  entirely  around 
and  square  across  the  rail.  Iron  rails  require  deeper  cutting 
than  steel  rails.  To  break  off  a  rail  at  the  cut,  lift  up  the 
end  nearest  the  cut  and  let  it  fall  across  a  piece  of  rail  laid 
on  a  tie.  If  but  a  short  piece  of  the  rail  is  to  be  broken  off,  a 
sharp  blow  from  a  sledge  is  the  surest  way  to  break  it. 
Hard  steel,  if  cut  too  deep,  is  liable  to  become  softened  by 
the  battering  of  the  chisel,  and  in  breaking  leave  a  rough, 
unshapely  end  on  the  rail.  A  spike  maul  should  not  be 
used  to  strike  the  head  of  either  chisel  or  punch,  as  it  is 


TRACK  WORK.  1151 

sure  to  destroy  the  face  of  the  maul  and  split  pieces  out  of 
the  head  of  steel  tools.  A  sledge  of  suitable  weight,  made 
for  the  purpose  of  striking  hard  steel  tools,  should  be  used 
instead. 

Cold  chisels  when  first  dressed  by  the  blacksmith  are 
not  always  well  tempered  at  the  point,  and  in  using  a  newly 
sharpened  chisel,  light  and  careful  blows  should  be  given 
first.  If  the  tool  is  well  tempered,  the  edge  will  hold,  but 
if  poorly  tempered,  the  edge  will  chip  slightly.  The  chisel 
should  then  be  ground  to  a  true  edge,  which  generally 
toughens  it,  and  it  will  cut  a  number  of  rails  before  it  is 
necessary  to  send  it  to  the  shop  again. 

1712.  Distance  at  Which  to  Place  Danger  Sig- 
nals.— Danger  signals  should  be  placed  at  distances  not 
less  than  3,500  feet  in  each  direction  from  the  point  where 
the  track  is  impassable  for  trains.  The  distance  can  be 
measured  by  counting  117  rails  of  30  feet  each  from  the 
point  of  danger,  or,  where  the  telegraph  poles  are  150  feet 
apart,  place  the  signals  23  poles  distant  from  the  point  of 
danger.  If  the  point  of  danger  is  at  the  foot  of  a  heavy 
grade,  where  it  is  difficult  to  stop  a  train,  the  distance  of 
the  danger  signal  should  be  increased  to  even  double  the 
ordinary  distance,  or  the  telegraph  operator  at  the  nearest 
station  informed  of  the  danger,  so  that  he  may  notify  the 
train  dispatcher,  who  will  at  once  warn  all  trains  within 
danger,  and  they  can  be  held  until  the  track  is  safe  for 
their  passage.  Where  there  is  a  suflficient  force  of  men  to 
make  repairs,  the  flagman  should  remain  with  the  danger 
signal  until  the  track  is  repaired  or  the  train  stopped. 
In  foggy  or  stormy  weather,  the  flagman  imist  ahi>ays 
remain  out  with  the  signals  until  all  danger  is  passed. 
As  soon  as  the  track  is  safe  for  the  passage  of  trains, 
flags,  torpedoes,  or  other  signals  should  be  removed  at 
once. 

Foremen  should  always  carry  flags  and  torpedoes  on 
their  hand  cars,  and  fully  instruct  their  men  in  the  use  of 
them.     They   should    be   fully  posted   on   the   time   of   all 


1152  TRACK  WORK. 

regular  trains,  and  should  be  on  the  watch  for  signals 
carried  by  regular  trains. 

1713.  Signals. — In  setting  a  signal  requiring  a  train 
to  run  slowly,  called  a  slow  flag,  place  the  flag  on  the 
engineer's  side  of  the  tracks  the  right  hand  side,  slightly 
leaning,  so  that  most  of  it  can  be  seen,  and  just  far  enough 
from  the  rail  to  clear  the  engine  and  cars. 

A  slow  signal  is  set  out  one-half  mile,  about  17  telegraph 
poles,  distant. 

A  red  flag  or  light,  which  is  a  stop  signal,  should  be  placed 
in  the  center  of  the  track.  Two  torpedoes  should  be 
placed  on  the  same  rail,  about  60  feet  apart,  between  the 
stop  signal  and  the  approaching  train. 

1714.  Location  of  Whistling  Posts  and  Signs. — 

Station  whistling  posts  should  be  placed  one-half  mile  out- 
side the  switch,  not  the  depot,  and  on  the  engineer's  side 
(the  right  side)  of  the  track  to  one  approaching  the  station. 
Station  mile  boards  should  be  placed  one  mile  outside  the 
switches.  If  the  post  were  placed  but  one  mile  from  the 
station,  it  would,  in  large  yards,  often  fall  inside  the 
switches.  The  object  of  these  signs  is  to  warn  trainmen  of 
the  near  approach  of  a  station  in  order  that  they  may  have 
the  train  under  control  before  reaching  the  station. 

Whistling  posts  for  highways  should  be  placed  one-quarter 
of  a  mile  from  the  crossing,  and  on  the  engineer's  side  of 
the  track.  Whistling  posts  or  other  signs  should  never  be 
placed  in  a  cut  where  they  will  not  be  readily  seen.  If  on 
a  descending  grade,  place  the  sign-  outside  the  cut,  increas- 
ing the  distance;  if  on  an  ascending  grade,  decrease  the 
distance.  This  rule  also  applies  to  sharp  curves.  All 
signs  carrying  a  cross-board  should  have  the  board  placed 
at  right  angles  to  the  track.  Highway  crossing  signs 
should  be  placed  parallel  to  the  rails,  so  that  they  may  be 
distinctly  read  by  persons  approaching  the  track.  All  posts 
carrying  signs  should  be  vertical,  and  securely  set  in  the 
ground,  and  so  placed  as  not  to  come  in  contact  with  either 
trains  or  vehicles. 


TRACK  WORK.  1153 

1715.  Obstructing  the  Track. — The  track  should 
never  be  so  used  as  to  obstruct  a  regular  train,  nor  should 
any  work  be  undertaken  which  can  not  be  finished,  and  the 
track  made  safe,  fully  15  minutes  before  the  train  is  due. 
In  case  of  a  delayed  passenger  train,  the  track  must  be 
kept  constantly  safe  and  clear,  and  if  repairs  must  be 
made,  a  responsible  man,  preferably  the  foreman  himself, 
should  remain  out  with  signals  until  the  track  is  safe  and 
clear. 

Some  foremen  have  a  habit  of  leaving  the  hand  or  push 
car  on  the  track  while  repairs  are  being  made.  This  is  a 
dangerous  practice,  and  contrary  to  the  rules  of  any  well- 
managed  railroad.  The  hand  car  should  not  only  be  kept 
clear  of  the  track  when  not  in  use,  but  should  not  be  left  in 
the  way  of  road  or  farm  crossings. 

1716.  Hand-Car  and  Tool  Houses. — Hand  car  and 
tool  houses  should  be  placed  outside  the  switches  at  yards 
and  stations,  so  that  trains  standing  on  the  side  track  will 
not  deter  section  men  with  their  hand  car  from  going  to 
work.  Tool  houses  must  be  far  enough  from  the  track  to 
prevent  obstructing  the  view  of  passing  trains. 

1717.  Throwing  Sivitches. — Foremen  should  not 
throw  switches  for  trivial  reasons.  An  empty  hand  car  or 
push  car  should  always  be  carried  from  one  track  to  another, 
and,  if  carrying  a  light  load,  it  can  be  handled  without 
throwing  a  switch.  Most  foremen  carry  a  switch  key,  but 
it  should  be  used  with  proper  discretion  and  never  -in  the 
absence  of  the  foreman.  The  person  tending  to  the  switch 
should  always  retnain  by  it  until  it  is  set  for  the  main  track 
and  locked.  Any  foreman  who  makes  a  practice  of  throw- 
ing switches  where  it  is  unnecessary  should  be  discharged 
at  once. 

1718.  Care  of  Tools. — The  section  foreman  is  re- 
sponsible to  the  railway  company  for  all  tools  and  other 
supplies  issued  to  him.  The  systematic  use  and  care  of 
tools  will  greatly  increase  their  efficiency  and  prolong  their 


1154  TRACK  WORK. 

service,  and  it  is  evident  that  the  foreman  can  not  better 
serve  his  company  than  by  instructing  his  men  in  the  proper 
handling  and  care  of  tools. 

Hand  cars  and  push  cars  should  be  oiled  regularly,  the 
axle  and  other  boxes  kept  tight,  and  the  cars  kept  always 
ready  for  service.  Hand  cars  should  not  be  used  to  carry 
steel  except  in  emergencies,  and  then  only  a  light  load 
should  be  taken,  the  rails  being  placed  on  both  sides  of  the 
car  so  as  to  balance.  Both  rails  and  ties  should  be  trans- 
ported on  the  push  car. 

Shovels  figure  largely  in  the  tool  account  chargeable  to 
track  repairs.  On  most  sections  this  account  is  unneces- 
sarily large,  owing  to  the  many  improper  uses  to  which  the 
shovel  is  put.  A  shovel  should  never  be  used  to  hold  up 
the  end  of  a  tie  for  spiking, -nor  driven  into  a  tie  in  place  of 
a  pick  to  pull  the  tie  into  its  trench  in  the  track.  As  soon 
as  the  edge  begins  to  turn,  it  should  be  straightened,  and, 
if  necessary,  trimmed  with  a  cold  chisel.  Proper  care  will 
often  double  the  life  of  a  shovel. 

Claw  bars  should  never  be  used  to  pry  up  the  track,  and, 
above  all,  in  frosty  weather,  as  the  claws  are  then  easily 
broken,  and  are  always  difficult  to  repair. 

1719.  Care  of  Material. — A  sure  test  of  a  good  fore- 
man is  his  care  for  all  material  placed  in  his  charge.  When- 
ever track  repairs  of  any  kind  are  made,  all  loose  material 
of  every  kind  should  be  collected,  and,  with  the  exception 
of  rails,  should  be  carried  to  the  section  house,  where  it 
may  be  sorted.  Much  old  material,  such  as  splice  bolts 
and  spikes,  rtiay,  with  a  little  straightening,  be  made  to 
serve  a  second  time  and  be  as  serviceable  as  new  mate- 
rial. All  old  iron  should  be  piled  in  places  convenient  to 
the  track,  whence  it  may  be  shipped  at  the  direction  of  the 
roadmaster. 

1720.  Care  of  Station  Grounds. — It  is  particularly 
to  the  section  foreman's  interest  to  keep  the  station  grounds 
in  perfect  order.  By  a  little  thought  and  planning,  he  can 
find  time  to  grade  the  approaches  to  the  station,  plant  a  few 


TRACK  WORK.  1155 

shade  trees,  and  do  some  sodding  where  it  will  tell.  This 
work  must  not  be  done  at  the  expense  of  regular  track  work, 
but  a  spare  hour  is  often  available,  and  the  results,  if  the 
time  has  been  wisely  expended,  amply  pay  for  the  outlay. 
Neat  station  grounds  encourage  travel,  and  are  sure  to  win 
the  approbation  of  superior  officers. 

1721.  Work-Train  Service.  —  The  foreman  in 
charge  of  a  work  train  should  make  it  his  business  to  keep 
his  men  at  work  whenever  the  train  is  delayed.  There  is 
always  plenty  of  work  to  do  along  the  track  at  any  point, 
and  by  proper  forethought  and  planning,  these  unavoidable 
delays  may  be  turned  to  full  account. 

Every  work  train  should  be  in  charge  of  a  thorough  track- 
man, who  should,  in  addition,  be  thoroughly  competent  to 
run  a  train. 

Work-train  conductors  and  foremen  in  pharge  of  gravel 
pits  or  of  steam-shovel  outfits  should  receive  their  orders 
from  and  be  responsible  to  the  roadmaster  of  the  division 
upon  which  they  are  working.  They  should  send  in  a  daily 
report  to  the  roadmaster,  and  every  evening  after  quitting 
send  in  to  the  dispatcher  a  lay-tip  report,  stating  where  they 
will  work  the  following  day.  Work  trains  should  always  lay 
up  at  a  telegraph  station. 

Conductors  in  charge  of  work  trains  should  see  that  all 
axle  boxes  are  properly  packed  and  oiled,  and  any  accidents 
to  cars  or  any  part  of  the  outfit  should  be  promptly  reported 
to  the  roadmaster. 

1722.  T.rack  Inspection. — There  shou4d  be  a  well- 
organized  system  of  track  inspection  on  every  railroad.  The 
amount  of  inspection  should  be  in  proportion  to  the  excel- 
lence of  the  track  and  the  amount  of  traffic.  Whatever  the 
amount  of  traffic,  the  entire  section  should  be  inspected  each 
day.  In  ordinary  weather  this  work  may  be  entrusted  to  a 
careful  section  hand,  but  in  stormy  weather  the  sect  ion  fore- 
man should  give  his  entire  section  a  careful  inspection.  It 
is  best  that  the  track  inspection,  especially  at  the  more  dan- 
gerous points,  should  be  made  before  the  passage  of  express 


1166  TRACK  WORK. 

trains.  On  double-track  roads  where  the  traffic  is  heavy, 
track  inspection  is  performed  by  regular  track  walkers.  They 
should  always  carry  a  track  wrench,  to  tighten  loose  bolts, 
and  a  flag  and  torpedoes  for  signals.  During  the  winter 
months,  when  the  ground  is  frozen  solid,  the  frost,  which 
hinders  many  kinds  of  general  track  work,  is  constantly 
heaving  the  track  out  of  line  and  surface,  and  greatly  in- 
creasing the  danger  of  accident.  A  rule  requiring  the  sec- 
tion foreman  to  see  his  entire  section  daily  should  be  strictly 
enforced.  During  extremely  cold  weather  the  track  requires 
constant  watching. '  During  heavy  storms,  it  is  a  good  plan 
to  go  by  train  against  the  storm,  to  the  end  of  the  section, 
and  inspect  the  track  while  returning  on  foot.  Two  or 
three  inspections  in  a  day  are  none  too  many  for  severe, 
stormy  weather. 

1 723.  Methods  of  Work. — Every  foreman  should  be 
on  the  alert  to  learn  new  and  approved  methods  of 
work.  By  careful  thought  he  may  devise  time  and 
labor-saving  methods  himself.  Work  slowly  done  is  not 
necessarily  well  done.  In  fact,  expedition  is  an  adjunct  to 
excellence,  as  no  man  can  do  work  rapidly  without  giving  it 
his  full  attention,  and  any  work,  however  simple,  that  has 
heart  put  into  it,  will  show  it  by  superior  excellence. 

1724.  Discipline. — A  foreman  to  succeed  must  be 
superior  to  his  men  both  in  knowledge  and  in  force  of  will. 
Abusive  and  profane  language  will  soon  demoralize  men, 
robbing  them  of  all  respect  for  their  foreman  and  for  them- 
selves. Patience  in  teaching  men  their  duties. and  habitual 
fair  treatment  will  make  an  enviable  reputation  for  any  fore- 
man. He  will  always  receive  prompt  and  efficient  service 
from  his  men,  can  always  count  on  a  full  gang,  and  can 
readily  increase  his  force  for  an  emergency.  Railroad  com- 
panies always  prefer  to  fill  their  important  offices  with  men 
who  have  been  tried  and  promoted  in  their  own  service.  The 
young  foreman  may  be  sure  that  competence  and  faithful- 
ness will  not  go  unrecognized  or  unrewarded.  He  should 
take  advantage  of   every  opportunity  to  increase  his  know- 


TRACK  WORK. 


1157 


ledge  of  his  craft,  and  do  all  in  his  power  to  make  it  rank  as 
a  profession. 

1725.  Section  Records. — Every  section  foreman 
should  keep  a  record  of  everything  connected  with  the  track 
under  his  charge.  This  record  should  be  neatly  and  clearly 
arranged,  and  should  contain  all  information  which  may  be 
used  as  a  basis  for  estimates,  for  the  location  of  structures, 
or  for  the  distribution  of  material. 

The  following  will  suggest  suitable  forms  for  such  a  record : 

SECTION  NO.  8- 

Length  of  section 6  miles  1,500  feet 

Length  of  east  side  track 1,200  feet 

Length  of  station  side  track 1,600  feet 

Length  of  west  side  track 1,400  feet. 


Bridge  Number. 

Number  of 
Bents. 

Length  of  Span. 

Distance  from 
Station. 

60 
61 
62 

4 

7 
Iron 

48  feet 
84  feet 
90  feet 

3    miles 
3f  miles 
4^  miles 

Culvert  Number. 

Box  Culvert. 

Iron  Pipe. 

Distance  from 
Station. 

176 

177 

1 

1 

1\  miles 
2    miles 

178 

1 

54-  miles 

Cuts,  Length 
in  feet. 

Height  above 
Rail. 

Material. 

Distance  from 
Station. 

One,  425 
One,  650 
One,  500 

6  feet 
4  feet 
8  feet 

Clay 

Gravel 

Rock 

2^  miles 
3|-  miles 
5    miles 

Steel  Rails, 
Amount. 

When  Laid. 

Brand. 

Extends  from 
Station. 

3  mi.    1,000  ft. 
3  mi.       500  ft. 

1884 

1889 

E.  Thompson 
L.  L  &  S.  Co. 

North 
To  end  of  Sec. 

1158  TRACK  WORK. 

1726.  Average   Day's  W^ork  for  One  Man. — The 

following  is  a  list  of  the  various  kind  of  labor  connected  with 
track  work,  and  gives  the  amount  of  each  which  a  good  man 
can  perform  in  one  day.  This  will  serve  to  show  the  relation 
existing  between  the  labor  of  one  man  and  a  gang  of  men  at 
any  of  the  different  kinds  of  work  specified: 

One  man  can 

Place  on  a  grade  one-eighth  of  a  mile  of  ties. 

Spike  one-tenth  of  a  mile  of  track  laid  on  soft  ties. 

Spike  one-fourteenth  of  a  mile  of  track  laid  on  hard  ties. 

Splice  and  bolt  one-sixth  of  a  mile  of  track. 

Clean  with  a  shovel  one-eighth  of  a  mile  of  average  weeds. 

Unload  10  cars  of  gravel. 

Unload  8  cars  of  dirt. 

Load  upon  cars,  18  to  24  cubic  yards  of  gravel. 

Load  upon  cars,  20  to  25  cubic  yards  of  dirt. 

Load  coal  into  buckets  for  engines,  15  to  20  tons. 

Unload  coal  into  sheds,  25  to  30  tons. 

Put  into  dirt  ballast  track,  20  new  ties. 

Put  into  gravel  ballast  track,  15  new  ties. 

Put  into  stone  ballast  track,  8  to  10  new  ties. 

Do  labor  equal  to  ballasting  60  feet  of  gravel  ballasted 
track. 

Do  labor  equal  to  ballasting  35  feet  of  stone  ballasted 
track. 

Chop  2  cords  of  4  ft.  wood. 

Make  15  to  25  hard  wood  ties. 

Make  35  to  40  soft  wood  ties. 

Sixty  men  can  lay  one  mile  of  track  in  a  day. 

1 727.  Tables  of  Material  Required  for  One  Mile 
of  Track : 


TRACK  WORK. 


1159 


TABLE  36. 


TONS   OF   RAILS    REQUIRED    PER    MILE    OF    TRACK. 


Weight 

Tons  (2,240  Lb.) 

Weight 

Tons  (2 

,240  Lb.) 

per  Yard. 

per  Mile. 

per  Yard. 

per 

Mile. 

Pounds. 

Tons.         Pounds. 

Pounds. 

Tons. 

Pounds. 

8 

12        1,280 

56 

88 

.... 

12 

18        1,920 

57 

89 

1,280 

16 

25           320 

60 

94 

640 

25 

39           640 

62 

97 

960 

28 

44 

64 

100 

1,280 

30 

47           320 

65 

102 

320 

35 

55 

68 

106 

1,920 

40 

62        1,920 

70 

110 

.... 

45 

70        1,600 

72 

113 

320 

48 

75           960 

76 

119 

960 

50 

78        1,280 

80 

125 

1,600 

52 

81        1,600 

To  find  the  number  of  gross 
one  mile  of  track: 

Rule. — Divide  the  weight  per 
quotient  by  11. 

Example.— For  70  lb.  rail.     70  h-  7  =  10;  10  x  11  =  110  tons. 


tons   of  rails  required  for 
yard  by  7  and  multiply  the 


TABLE  37. 


NUMBER   OF  CROSS-TIES  PER   MILE. 


Distance,  Center 
to  Center. 

Number  of  Ties. 

\\  feet 

3,520 

If  feet 

3,017 

2     feet 

2,640 

2i  feet    ' 

2,348 

2^  feet 

2,113 

2|  feet 

1,921 

3     feet 

1.761 

1160 


TRACK  WORK. 


TABLE  38. 


NUMBER  OP  RAILS,  SPLICBS,  AND  BOLTS  PER  MILE  OP 

TRACK. 


Length  of  Rail. 

No.  of  Rails 
per  Mile. 

No.  of  Splices. 

No.  of  Bolts, 

4  to  Each 

Joint. 

No.  of  Bolts, 

6  to  Each 

Joint. 

18  feet 

584 

1,168 

2,336 

3,504 

20  feet 

528 

1,056 

2,112 

3,168 

21  feet 

503 

1,006 

2,012 

3,018 

22  feet 

480 

960 

1,920 

2,880 

24  feet 

440 

880 

1,760 

2,640 

25  feet     . 

422 

844 

1,688 

2,532 

26  feet 

406 

812 

1,624 

2,436 

27  feet 

391 

782 

1,564 

2,346 

28  feet 

377 

754 

1,508 

2,262 

30  feet 

352 

704 

1,408 

2,112 

TABLE    39. 


RAILROAD  SPIKES  PER   MILE  OP  TRACK. 


Size  Measured 
Under  Head. 

Average  Num- 
ber per  Keg 
of  200  lb. 

Ties  2  Ft.  Between 

Centers, 
4  Spikes  to  a  Tie. 

Rails  Used, 

Pounds 

per  Yard. 

Pounds. 

Kegs. 

H  X  tV 

375 

5,870 

2H 

45  to  70 

5    Xt\ 

400 

5,170 

26 

40  to  56 

5    X   i 

450 

4,660 

23i 

35  to  40 

4iX   i 

530 

3,960 

20 

28  to  35 

4    X   i 

600 

3,520 

17f 

24  to  35 

Hx^ 

4    XtV 

680 
720 

3,110 
2,910 

15^ 
141 

i  20  to  30 

Hx^ 

4    X   f 

900 
1,000 

2,350 

2,090 

11 
10^ 

[   16  to  25 

Hx  1 

3    X   1 

1,190 
1,240 

1,780 
1,710 

9 
8i 

[•   16  to  20 

nx  i 

1,342 

1,575 

n 

12  to  16 

TRACK  WORK. 


IIGI 


TABLE  40. 


NUMBER    OF   TRACK   BOLTS   IN   A   KEG  OF  200  LB- 


Rails  Used. 

Bolts. 

Size  Nuts. 

Bolts  in  Keg. 

Kegs  per  Mile. 

40  to  70 

|X4i 

Usq. 

195 

7.3 

40  to  70 

f  X  4 

Hsq. 

200 

7.1 

40  to  70 

|X3| 

lisq. 

208 

7.0 

40  to  70 

f  X3i 

Hsq. 

216 

(}.6 

25  to  40 

f  X4 

Usq. 

305 

4.7 

25  to  40 

f  X3i 

lisq. 

329 

4.3 

25  to  40 

iXU 

1    sq. 

.  576 

2.6 

18  to  20 

i  X  2i 

1    sq. 

654 

3.3 

40  to  70 

1  X  3^ 

If  hex. 

170 

8.3 

40  to  70 

|X  3f 

If  hex. 

237 

6.0 

40  to  70 

f  X3i 

1^  hex. 

228 

6.3 

40  to  70 

f  X  4 

If  hex. 

220 

6.5 

25  to  40 

tx3^ 

1    hex. 

415 

3.4 

RAILROAD   STRUCTURES. 


WOODEN    TRESTLES. 

1 728.  Extent  of  Trestling. — The  amount  of  wooden 
trestling  in  use  on  American  roads  is  very  large,  and  covers 
a  wide  range  in  both  material  and  design.  As  the  period  of 
construction  is  always  a  severe  test  of  the  financial  strength 
of  a  railroad  com'pany,  it  has  been  the  almost  universal 
policy  in  this  country  to  use  temporary  structures  of  moder- 
ate cost,  wherever  possible,  and  to  defer  the  erection  of 
permanent  structures  until  traffic  is  on  a  paying  basis  and 
finances  are  easy.  Hence  it  follows  that  of  the  2,500  miles 
of  trestle  now  in  use  on  American  roads,  fully  one-quarter  will 
be  replaced  by  embankment.  Of  the  remaining  1,900  miles, 
at  least  800  miles  will  be  maintained  in  wood.  It  is,  there- 
fore, a  matter  of  great  importance  that  these  structures, 
whether  temporary  or  permanent,  should  be  well  planned 
and  constructed  in  order  that  they  may  best  meet  the 
requirements  of  safety  and  economy. 

1729.  Average  Life  of  a  Wooden  Trestle. — The 

average  life  of  a  wooden  trestle  is  taken  at  8  years,  and 
the  question  of  renewal  will  depend  upon  the  compara- 
tive cost  of  an  embankment  with  the  requisite  amount  of 
masonry  for  watercourses,  or  for  the  rebuilding  of  the 
wooden  structure  at  intervals  of  8  years.  Trestles  which  are 
to  be  replaced  by  embankments  may  properly  differ  consider- 
ably in  design  from  those  which  are  to  be  periodically  re- 
newed. Temporary  trestles  should  possess  the  qualities  of 
simplicity  and  strength  alone,  while  those  which  are  to  be 


1164 


RAILROAD   STRUCTURES. 


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RAILROAD    STRUCTURES.  1165 

maintained  in  wood  should  be  so  designed  that  they  may  be 
renewed  without  any  interruption  of  traffic.  In  either  case, 
the  use  of  any  other  than  the  best  available  material  is  to  be 
condemned  as  poor  economy.  The  cost  of  the  construction 
of  a  trestle  is  a  considerable  percentage  of  its  total  cost,  and 
is  but  slightly  affected  by  the  character  of  the  materials  com- 
posing it,  and,  hence,  the  small  saving  effected  by  the  use 
of  cheaper  materials  is  neutralized  by  the  shortened  life  of 
the  structure  and  its  general  lack  of  excellence 

A  good  wooden  structure  is  preferable  to  a  cheap  iron  one, 
though  the  impression  commonly  prevails  that  an  iron 
structure  must  necessarily  be  strong  and  efficient.  Many 
new  lines  traverse  sections  where  timber  is  abundant  and 
cheap,  bringing  the  cost  of  wooden  structures  within  safe 
reach  of  the  railroad  company,  whereas  costly  structures  of 
iron  or  heavy  fills  might  have  wrecked  the  company  and  the 
enterprise. 

1 730.  Comparative  Cost  of  Trestles  and  Em- 
bankments.— The  height  at  which  it  becomes  more  eco- 
nomical to  substitute  trestling  for  embankment  varies 
widely,  depending  upon  the  locality,  the  cost  of  timber, 
labor,  and  the  character  of  material  available  for  making  the 
fill.  There  are,  of  course,  many  situations,  such  as  deep 
swamps  or  waterways,  where  an  embankment  is  out  of  the 
question.  It  then  becomes  a  choice  between  wooden  and 
iron  structures. 

The  cost  of  an  embankment  increases  in  a  vastly  greater 
ratio  than  its  height,  as  will  be  seen  from  Table  41.  The 
cost  of  trestling,  on  the  other  hand,  does  not  increase  nearly 
as  rapidly  as  its  height,  especially  for  heights  under  50  feet. 
The  cost  of  pile  and  framed  trestles  for  heights  from  5  to 
45  feet,  inclusive,  is  given  in  Table  42. 

1731.  Mathematical  Formulas  of  Slight  Use  in 
Trestle  Designing. — Few  engineers  employ  mathematical 
formulas  in  designing  trestles.  The  strength  and  properties 
of  timber  vary  with  each  separate  piece,  and  in  proportioning 


1166 


RAILROAD    STRUCTURES. 


the  parts  of  a  trestle  it  is  far  safer  to  rely  upon  one's  own 
judgment,  if  supported  by  large  experience,  or  to  follow 
the  approved  examples  of  other  men,  than  to  rely  upon  any 
set  of  mathematical  formulas.  American  railroads  show  a 
wide  range  in  trestle  design,  each  important  road  having 
a  set  of  standard  designs  which  may  differ  more  or  less  from 
those  employed  on  other  lines.  The  designs  given  in  this 
paper  are  copies  of  some  of  the  best  standards  in  use  on 
American  roads,  and  cover  a  range  wide  enough  to  meet  the 
requirements  of  all  ordinary  situations. 

TABLE    42. 

Cost  of  Pile  and  Framed  Trestles,  complete,  including 
Floor  Systems  for  Different  Heights  in  Sections  of  100 
feet. 


Height 

Pile. 

Framed. 

in  Feet. 

$30 

$35 

$40 

$30 

$35 

$40 

5 

1546 

$605 

$665 

$453 

$528 

$604 

10 

611 

674 

738 

555 

647 

740 

15 

678 

742 

806 

634 

739 

844 

20 

746 

811 

877 

711 

829 

947 

25 

918 

1,001 

1,084 

966 

1,126 

1,286 

30 

986 

1,070 

1,154 

1,042 

1,215 

1,389 

35 

1,160 

1,263 

1,366 

1,228 

1,432 

1,636 

40 

1,227 

1,332 

1,444 

1,303 

1,520 

1,736 

45 

1,372 

1,602 

1  832 

1 732.     Classes    of    Trestles. — Wooden    trestles   are 

divided  into  two  general  classes,  viz.,  pile  trestles,  in  which 
the  bents  consist  of  piles  united  by  a  cap,  and  framed 
trestles,  in  which  the  bents  consist  of  squared  timbers 
framed  together.  Pile  trestles  are  rarely  used  for  heights 
exceeding  30  feet.      Framed  trestles  may  be  of  almost  any 


RAILROAD    STRUCTURES. 


1167 


height,  though  special  designs  are  required  for  those  ex- 
ceeding a  height  of  30  feet. 


Fig.  548. 


1733.  Technical  Terms  and  IVames. — In  order 
that  the  student  may  understand  the  various  parts  com- 
posing a  trestle,  the  following  technical  terms  and  names  are 


V      0° 

°o  4 

n              m 

V 

*. 

8^ 

Fig.  549. 


given,  the  number  accompanying  each  term  corresponding 
to  the  parts  given  in  Figs.  548  and  549: 


1168 


RAILROAD    STRUCTURES. 


Bent,  Framed,  1. 
Bent,  Pile,  2. 
Cap,  3. 
Cross-tie,  4. 
Dapping,  5. 

Gaining,  see  Dapping,  5. 
Guard-rail,  0. 
Jack-stringer,  7. 
Longitudinal  Brace,  8. 
Mortise,  9. 
Mud-sill,  10. 

Notching,     Gaining,     Dap- 
ping, 5. 
Packing-block,  11. 


Packing-bolts,  12. 

Piles,      Batter,       Inclined, 
Brace,  13. 
Vertical,  Plumb,  Upright, 
14. 

Posts,  Vertical,  Plumb,  Up- 
right, 15. 
Batter,  Inclined,  16. 

Sill,  17. 

Stringer,  18. 

Sway-brace,  19. 

Tenon,  20. 

Waling-strip,    see    Longi- 
tudinal Brace,  8. 


1734.     Pile  Bents. — As  the  subject  of  pile  driving 

was  fully  discussed  in  the  section  on  Railroad  Construction, 
no  reference  will  be  made  in  this  section  to  the  theory  of  pile 
driving.  Where  the  line  traverses  low,  marshy  ground, 
either  constantly  overflowed  or  subject  to  occasional  over- 
flow, and  where  the  height  of  the  rails  above  the  surface  of 
the  ground  does  not  exceed  30  feet,  a  pile  bent  is  generally 
adopted.  When  pile  bents  are  used  for  greater  heights  than 
30  feet,  only  the  tops  of  the  piles  penetrate  the  ground,  and 
though  they  may  reach  a  substantial  bottom,  the  bent  is 
essentially  weak,  owing  to  the  small  diameter  of  the  pile 
and  the  small  proportion  of  heart  timber  at  the  top  of  the 
tree.  It  is  the  heart  timber  alone  which  can  long  resist 
decay,  and  at  the  surface  of  the  ground,  where  the  timber  is 
alternately  wet  and  dry,  decay  sets  in  as  soon  as  the  struc- 
ture is  erected,  and  in  a  few  years,  at  best,  the  piles  must  be 
renewed,  though  the  remainder  of  the  trestle  may  be  in  a 
comparatively  sound  condition. 

Piles  should  be  cut  from  live,  straight,  thrifty  trees,  free 
from  dead  or  loose  knots,  wind  shakes,  and  all  descriptions 
of  decay,  and  be  stripped  of  bark.  They  should  have  a  butt 
diameter  of  from  12  to  15  inches,  and  a  top  diameter  of  from 
7  to  10  inches  inside  the  bark.     Squared  piles  are  used  in  a 


RAILROAD   STRUCTURES. 


1169 


limited  way,  and  when  so  used  they  should  measure  12  inches 
square  at  the  butt,  and  not  show  more  than  2  inches  of  sap 
wood  on  the  corners.  It  is  the  custom  on  some  lines  to 
paint  the  pile  for  a  short  distance  above  and  below  the 
ground  line  with  hot  tar,  thus  tending  to  retard  decay. 

Timber  suitable  for  piles  may  be  found  in  most  sections 
of  the  United  States.  The  different  varieties  of  timber 
commonly  used  for  piling  are  named  in  the  following  list  in 
the  order  of  their  excellence: 


Red  Cedar, 
Black  Cypress, 
Pitch  Pine, 
Yellow  Pine 
(long-leaf), 


White  Pine, 
Redwood, 
Elm, 
Spruce, 


White  Oak, 
Post  Oak, 
Tamarack, 
Hemlock. 


The  arrangement  of  the  piling  forming  the  bent  varies 
considerably  with  different  constructors  in  the  matter  of 


I-    5*0 


12-0 


4-0 


s 


14-0' 


33r 


4-6 


fh 


!    i  i   I       I    i 

Figs.  550  and  551. 


Figs.  552  and  553. 


spacing  the  piles,  though   the  general  arrangement  is  the 
same. 

For  a  height  of  bent  not  exceeding  5  feet,  and  where  the 


1170  RAILROAD    STRUCTURES. 

road  is  to  carry  only  a  moderate  traffic,  a  three-pile  bent  is 
generally  adopted,  one  pile  being  placed  directly  upon  the 
center  line  and  the  others  spaced  from   3  feet  6  inches  to 

5  feet  out,  the  piles  being  driven  vertically.  (Fig.  550.) 
For  trunk  lines,  however,  whatever  the  height,  all  bents 
should  contain  four  piles. 

For  heights  of  from  5  to  15  feet,  each  bent  should  contain 
four  piles  driven  vertically.  The  inner  piles  may  be  spaced 
from  4  to  5  feet  and  the  outer  ones  about  11  feet  from  center 
to  center.  (Fig.  551.)  Pile  bents  of  this  height  will  not 
require  sway  bracing,  provided  the  penetration  amounts  to 

6  or  8  feet  in  firm  earth.  For  heights  exceeding  15  feet,  it 
is  well  to  batter  the  outside  piles,  as  shown  in  Fig.  552.  By 
this  means  the  width  of  the  base  is  considerably  increased, 
giving  in  appearance,  as  well  as  in  fact,  greater  stability  to 
the  structure.  Piles  are  battered  from  2  to  4  inches  to  the 
foot,  3  inches  being  commonly  adopted. 

On  Western  roads,  vertical  pile  bents  of  heights  of  20 
feet  and  over  are  frequently  seen,  but  they  give  the  im- 
pression of  a  lack  of  stability,  which  the  battered  piles  at 
once  remove.  Where  the  diameter  of  the  pile  at  the  cut-off 
point  exceeds  the  width  of  the  cap,  the  part  of  the  pile 
which  projects  should  be  adzed  off  at  an  angle  of  45°, 
(Fig.  553.) 

1 735.  Splicing  Piles. — When  the  material  into  which 
the  piles  are  driven  is  soft  ground,  extending  to  a  great 
depth,  it  may  be  necessary  to  splice  the  piles  in  order  to 
reach  a  firm  foundation.  In  splicing,  the  piles  are  placed 
end  to  end,  and  united  either  by  dowels,  bands,  or  scarf- 
ings.  Three  different  forms  of  splices  are  shown  in  Figs. 
554,  555,  and  55G.  Those  shown  in  Figs.  554  and  555  are 
commonly  adopted.  The  first  pile  is  driven  until  its  top  is 
within  easy  reach  from  the  surface  of  the  ground.  It  is 
then  cut  off  and  trimmed  up  for  splicing,  and  the  second 
pile  placed  upon  and  fastened  to  it.  When  the  ground  is 
in  a  partially  fluid  state,  the  pile  already  driven  will  have 
but  little  stiffness,  so  that  if  either  of  the  splices  shown  in 


RAILROAD   STRUCTURES. 


1171 


Fig.  554. 


Fig.  555. 


Fig.  556. 


Figs.  554  and  555  is  used,  the  piles  are  liable  to 
cant  in  driving  and  the  splice  to  give  way.  In 
such  cases  it  is  better  to 
strengthen  the  splice  with 
scarfings,  say  3  inches  by  3 
inches  by  8  or  10  feet  in 
length,  spiked  to  the  piles  as 
shown  in  Fig.  556.  This 
splice  was  used  in  the  false 
work  for  the  erection  of  the 
Poughkeepsie  bridge,  and 
proved  very  efficient.  When 
the  band  splice  (Fig.  555)  is  used,  some  de- 
vice must  be  used  to  keep  the  band  in  place, 
else,  after  a  few  blows  of  the  hammer,  it  will 
be  found  wholly  on  one  pile  or  the  other.  Rail- 
road spikes  driven  above  and  below  the  band,  as 
shown  in  Fig.  555,  will  prevent  this  movement. 

1736.  Determining  the  Length  of 
Piles  Required. — If  the  bridge  is  to  be  a 
long  one,  requiring  a  large  number  of  piles,  it 
'is  important  that  the  approximate  lengths  of  the 
piles  required  and  the  number  of  each  should  be 
known  before  ordering  the  material.  The  fol- 
lowing method,  adopted  by  the  Northern  Pacific 
Railroad  Company  for  their  bridge  over  the  St. 
Louis  river,  at  Duluth,  proved  very  satisfactory. 
Test  piles  were  driven  every  300  feet  along  the 
center  line,  and  where  any  considerable  variation 
in  penetration  was  noticed,  an  intermediate  pile 
was  driven.  The  piles  were  driven  from  a  scow, 
the  space  between  the  piles  being  regulated  by  a 
rope  attached  to  the  last  pile  driven.  After  the 
piles  were  all  driven,  their  exact  location  was  de- 
termined by  triangulation.  A  careful  record  was 
kept  of  the  driving  of  each  test  pile,  the  notes 
being  kept  in  the  following  form; 


1172 


RAILROAD    STRUCTURES. 


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RAILROAD    STRUCTURES. 


1173 


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1737.  Record  Ta- 
bles of  Progress  and 
Cost  of  Pile  Driving. — 

The  penetration  of  the 
pile  was  not  measured 
until  the  rate  of  sinking 
indicated  firm  bottom,  af- 
ter which  the  penetration 
was  measured  for  the  last 
twenty  or  thirty  blows, 
in  sets  of  ten  consecutive 
blows.  In  all  cases  the 
piles  were  driven  until  the 
requirements  of  the  speci- 
fications were  met,  viz.,  a 
20-foot  fall  of  a  2,000  lb. 
hammer  to  cause  a  pene- 
tration not  to  exceed  1 
inch.  The  notes  relatin-g 
to  the  size  and  driving 
of  the  pile  were  taken  by 
the  inspector  at  the  time, 
the  elevations  by  the  en- 
gineer afterwards.  A 
profile  was  then  made  up 
from  these  notes,  and  the 
piles  ordered  according 
to  the  lengths  measured 
upon  this  profile.  This 
scheme  for  estimating 
piling  from  actual  tests 
proved  a  complete  suc- 
cess, there  being  few  dis- 
crepancies between  the 
material  in  place  and  that 
ordered.  The  waste  of  ma- 
terial was  consequently 
reduced  to  a  minimum. 


1174 


RAILROAD   STRUCTURES. 


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II 

RAILROAD   STRUCTURES. 


117^ 


A  permanent  record  of  each  structure  should  be  made  in 
detail  during  construction  for  the  future  use  of  the  main- 
tenancc-of-way  department.  An  excellent  form  of  such  a 
record,  and  the  one  used  on  the  above  work,  is  given  here.  . 

This  gives  actual  cost  of  driving  after  the  piles  were 
delivered  at  the  pile  driver,  but  it  is  a  very  low  average  of 
cost,  the  work  being  done  by  the  firm  of  Winston  Bros.,  of 
Minneapolis,  noted  for  their  energy  and  excellence  of  plant 
equipment. 

In  making  approximate  estimates  of  cost  of  piling  and 
trestles,  when  exact  data  are  not  available,  the  preceding 
table  of  cost  will  serve  as  a  safe  guide,  as  it  is  based  on 
actual  contract  prices. 

1  738.  Capping  Piles. — When  a  floating  pile  driver  is 
used,  the  sawing  off  and  capping  of  the  piles  may  follow  the 


Fig.  557. 


driving,  at  the  convenience  of  the  contractor,  though  it  is 
better  to  follow  the  driving  closely  with  the  caps  and 
stringers.  When  a  land  driver  is  used,  each  bent  must  be 
cut  off  and  capped  and  timbers  laid  before  the  driver  can 
advance  to  the  next  bent.  As  soon  as  a  bent  of  piles  is 
ready  for  cutting  off,  the  height  of  the  top  of  pile  is  given 
with  an  instrument,  and  a  narrow,  straight-edged  strip  of 
board  (ordinary  roofing  lath  serves  well)  is  nailed  on  each 
side  of  the  bent,  with  its  top  edge  at  the  proper  height  for 
cutting  off.  (Fig.  557.)  The  cutting  off  is  best  done  with  a 
cross-cut  saw  worked  by  two  men.  If  the  piles  are  tenoned 
to  the  caps,  the  cutting  necessary  to  form  the  tenon  is  done 
with  the  cross-cut  saw. 


117G 


RAILROAD   STRUCTURES. 


1 739.  Caps  may  be  fastened  to  the  piles  in  three  differ- 
ent ways,  viz. :  By  mortise  and  tenon,  by  drift  bolts,  or  by 
dowels.  For  solid  caps,  a  tenon  3  inches  thick,  8  inches 
wide,  and  5  inches  long  is  a  good  size  (see  Fig.  558).     The 

top  edges  of  the  tenon  should  be  chamfered 
and  the  mortise  and  tenon  made  so  as  to  fit 
snugly.  The  parts  are  held  together  by 
means  of  wooden  pins,  called  treenails.  Tree- 
nails are  from  1  mch  to  1^  inches  in  diameter, 
and  slightly  tapering  (see  Fig.  558).  They 
should  be  made  of  hard  wood,  oak  or  locust 
to  be  preferred.  The  hole  made  in  the  cap 
to  receive  the  pin  should  be  spaced  a  little 
further  from  the  base  of  the  cap  than  the  hole 
in  the  tenon  from  the  tenon  shoulder,  so  that 
in  driving  the  pin,  the  parts  will  be  drawn  together.  Iron 
bolts  or  pins  should  never  be  used  in  place  of  wooden  pins. 
Instead  of  crowding  or  drawing  the  parts  together,  the  iron 
punches  or  cuts  away  any  wood  which  lies  in  its  path, 
merely  increasing  the  size  of  the  hole. 

1740.  When  drift  bolts  or  dowels  are  used,  the  piles 
are  cut  off  level,  and  holes  are  bored  in  both  cap  and  pile 
to  receive  the  drift  bolt  or  dowel.  Sometimes  two  drift  bolts 
or  dowels  are  used  at  each  pile,  but  commonly  only  one. 


Fig.  559  Fig.  560.  Fig.  561. 

which  is  amply  sufficient.  A  hole  is  first  bored  through  the 
cap  into  the  pile  head  to  receive  the  drift  bolt,  which  should 
be  somewhat  larger  than  the  hole,  so  that  in  driving,  every 
cavity  in  the  hole  may  be  completely  filled  (see  Fig.  559). 


RAILROAD    STRUCTURES.  1177 

1741.  Dowels  are  of  shorter  length  than  drift  bolts 
and  extend  only  about  half  way  through  the  caps  (see 
Fig.   5G0). 

Another  method  of  fastening  caps  to  piles,  and  one  which 
is  rapidly  growing  in  favor,  is  by  means  of  split  caps,  shown 
in  Fig.  561,  in  which  the  cap,  instead  of  being  a  single  piece 
of  timber,  consists  of  two  pieces,  each  half  the  size  of  the 
single  piece. 

For  example,  instead  of  using  for  the  cap  a  single  stick 
of  timber  12  inches  by  12  inches,  as  shown  in  Figs.  559  and 
560,  we  substitute  two  pieces  a  and  b  (Fig.  561),  each 
6  inches  by  12  inches.  A  tenon  r,  3  inches  wide  and  extend- 
ing the  full  width  of  the  pile,  is  formed  at  its  top,  and  a  cap 
is  placed  on  each  shoulder  against  the  tenon.  A  f -inch  bolt 
^  is  passed  through  the  caps  and  tenon,  holding  them  firmly 
in  place.  The  caps  should  not  be  notched,  and  the  piles 
should  be  sawed  off  smooth  and  level,  so  as  to  afford  a  good 
bearing  for  the  caps.  Some  of  the  advantages  claimed  for' 
split  caps  are  the  following: 

1st.  On  account  of  smaller  size,  better  timber  can  be 
obtained  at  less  cost. 

2d.  Repairs  can  be  made  with  ease  and  great  economy  of 
time  and  labor. 

3d.  Traffic  need  not  be  interrupted  nor  endangered  while 
repairs  are  being  made. 

4th.  The  caps  may  be  replaced  without  cutting  or 
injuring  any  other  part  of  the  structure. 

oth.  Economy  in  material,  because  it  is  not  necessary  to 
replace  the  whole  cap  unless  both  sticks  are  decayed,  but 
only  that  part  which  is  no  longer  in  a  serviceable  condition. 


FRAMED    BENTS. 

1742.  Foundations. — Framed  bents  are  composed 
entirely  of  sawed  timber,  and  are  placed  upon  a  foundation, 
the  objects  of  which  are  to  ensure  stability  to  the  structure, 
and,  by  raising  it  from  the  ground,  to  prolong  its  life.  All 
timber  placed  in  direct  contact  with  the  ground  partakes  of 


1178 


RAILROAD   STRUCTURES. 


all  its  changing  conditions  of  drouth  and  moisture,  which 
soon  induce  decay.  It  is  also  desirable  that  the  foundation 
should  be  as  little  affected  by  changes  of  temperature  and 
moisture  as  possible.  Among  the  various  kinds  of  founda- 
tions used  for  trestle  bents  are  the  following:  masonry,  pili\ 
sub-sill,  grillage,  crib,  solid  rock,  and  loose  rock. 

1743.  Masonry  foundations  are  the  best.  They  are 
ordinarily  composed  of  rubble  masonry,  laid  either  in  lime 
or  cement  mortar.  The  latter  is  recommended,  as  it  is  not 
aflfected  by  moisture. 

Suitable  masonry  foundations  are  shown  in  Figs.  502  and 
563.  In  northern  latitudes,  trenches  at  least  12  inches  in 
depth  should  be  excavated  for  these  foundations,  to  prevent 


their  being  heaved  by  hard  freezing.  In  exposed  localities, 
where  the  freezing  is  more  severe,  it  may  be  necessary  to 
excavate  the  foundation  trenches  to  a  depth  of  2  feet. 

It  is  bad  policy  to  use  irregularly  shaped  stone,  especially 
cobble  stone,  in  building  trestle  foundations.  The  continual 
jar  caused  by  passing  trains  is  liable  to  seriously  injure  ma- 
sonry of  an  inferior  quality.  Dry  rubble,  if  built  of  long 
stones  with  horizontal  beds,  and  well  bonded,  is  much  supe- 
rior to  mortar  rubble  of  poor  quality.  The  foundation  walls 
shown  in  Figs.  502  and  563  are  supposed  to  be  laid  in  foun- 
dation pits  12  inches  deep,  and  to  extend  2  feet  above  the 
surface  of  the  ground.  The  ends  of  the  wall  should  be 
vertical,  and  the  sides  battered  about  2  inches  to  the  foot. 

When  pile  foundations  are  employed  for  marshy  ground 
of  not  too  great  depth,  it  is  a  good  plan  to  allow  the  piles  to 
extend  far  enough  above  the  surface  of  the  ground  to  form 
a  bent,  which  is  capped  and  a  framed  bent  placed  on  top  of 


RAILROAD   STRUCTURES. 


lltO 


it.  Where  the  trestle  crosses  a  waterway,  it  is  good  practice 
to  place  a  framed  bent  upon  a  pile  foundation  of  such  height 
as  to  remain  always  under  water.  The  decay  due  to  alter- 
nate wetting  and  drying  is  thus  confined  to  the  framed 
portion,  which  can  easily  be  renewed. 

1744.  Sub-sills,  or  mud-sills,  are  blocks  of  timber 
placed  under  the  main  sills  to  raise  them  above  the  ground 
and  so  prevent  decay.  Some  recommend  planks  3  or  4  inches 
in  thickness,  but  12-inch  by  12-inch  timber  is  far  better, 
and  the  additional  cost  is  trifling  compared  with  the  solidity 
of  foundation  and  security  agamst  decay.  The  sills  and  sub- 
sills  should  be  fastened  together,  to  prevent  the  latter  from 
being  displaced.     As  the  strain  is  slight,  G-inch  cut  spikes, 


FIG.  564. 

driven   as   shown   at   «,  a,    in   Fig.    564,  will   serve   for  a 
fastening. 

1745.  A  grillage  of  timber  may  be  employed  as  a 
foundation  when  the  trestle  crosses  a  marsh  extending  to  a 
great  depth,  but  covered  by  a  layer  of  earth  possessing  con- 
siderable supporting  power.  Such  marshes  are  frequent 
in  Canada  and  the  States  bordering  on  Canada.  The  grill- 
age may  be  constructed  either  of  sawed  or  round  timber, 
according  to  which  is  the  most  available.  The  grillage  shown 
in  Fig.  5G5  was  employed  on  the  Northern  Adirondack  Rail- 
road in  crossing  a  subterranean  lake.  The  lake  was  covered 
with  earth  to  the  depth  of  several  feet  and  overgrown  with 
brush  and  timber,  but  was  unsafe  for  an  embankment.  The 
longest  piles  failed  to  reach  bottom,  and  the  grillage  shown 
in  the  figure  was  employed.  Each  bent  was  supported  by 
four  logs  or  rangers  laid  lengthwise  the  bent,  and  cross-tied 


1180 


RAILROAD   STRUCTURES. 


by  short  logs  which  were  drift-bolted  to  the  rangers.  The 
logs  were  notched  at  each  intersection,  as  shown  in  the  de- 
tail at  A.  The  tops  of  the  cross  logs  were  adzed  at  their 
middle  to  a  common  level  to  receive  the  bent  sills  which 
were  drift-bolted  to  the  grillage.  By  this  means  the  weight 
of  the  trestle  and  trainload  was  distributed  over  a  consid- 
erable area.     Though  the  road  has  been  in  operation  more 


mEj 


X4-0 — 


iriKm 


h 8-0 ■\ 


Fig.  565. 


than  a  dozen  years,  no  considerable  settlement  has  taken 
place. 


1  746.  Cribs  may  be  employed  for  foundations  where 
the  ground  is  very  sidling,  or  they  may  be  used  as  a  sub- 
stitute for  masonry  foundations  where  the  line  crosses  or 
borders  on  streams  with  rapid  currents.  At  such  points 
timber  and  cobble  stones  for  ballast  are  often  to  be  had  for 
the  asking,  when  masonry  would  prove  very  expensive. 

A  crib  suitable  for  such  foundations  is  shown  in  Fig.  566. 


RAILROAD   STRUCTURES. 


1181 


The  crib  is  of  pyramidal  form  and  built  entirely  of  round 
timber,  notched  together  as  shown  in  Fig.  505.  On  side 
hill  ground,  the  surface  is  broken  up  into  steps,  as  shown  in 
the  figure.  The  logs  are  drift-bolted  together  at  the  joints, 
and  the  enclosed  spaces  filled  with  stone.  The  crib  should 
be  long  enough  at  the  top  to  contain  the  sills,  after  full 


Fig.  566. 

allowance  has  been  made  for  the  batter  posts.  This  makes 
a  cheap  and  substantial  foundation,  and  it  can  be  easily 
built  in  a  swift  current  of  water. 

1 747.  If  the  surface  is  solid  rock,  all  that  is  neces- 
sary in  preparing  a  foundation  is  to  smooth  off  a  place  for 
each  post  to  stand  on.  The  readiest  way  to  fasten  each  post 
is  by  means  of  a  dowel,  which  should  reach  5  or  6  inches 
into  the  rock  and  an  equal  distance  into  the  post.  In  some 
instances,  holes  are  blasted  into  the  surface  rock,  and  the 
posts  stood  in  the  holes.  After  the  posts  are  fastened  to- 
gether, forming  a  bent,  the  vacant  space  about  the  foot  of 
each  post  is  filled  with  rich  cement  mortar.  When  such 
foundations  are  used,  the  system  of  bracing  should  be  ample, 
especially  where  the  trestle  is  built  on  a  side  hill  requiring 
posts  of  much  greater  length  on  the  lower  than  on  the  upper 
side. 

1748.  Loose  Rock. — Where  masonry  foundations 
would  prove  too  costly,   satisfactory  foundations  may  be 


1182 


RAILROAD   STRUCTURES. 


made  of  loose  rock.     These  are  made  by  excavating  a  short 
trench  directly  under  each  post,   as    shown  in    Fig.    5fi7. 


Fig.  567. 

These  trenches  are  filled  rounding  full  of  broken  stone,  and 
sub-sills  placed  upon  them,  forming  the  supports  for  the  sills. 
If  water  accumulates  in  the  trenches,  it  may  be  drained  olT 
by  digging  shallow  open  ditches  around  the  foundations  and 
leading  them  away  to  lower  ground.  This  will  at  least  save 
the  sub-sills  from  contact  with  water  and  so  preserve  them 
from  rapid  decay. 

1749.     Drip   Holes. — The  tendency  of  water   to  ac- 
cumulate in  mortises  hastens  decay  of  the   timbers.     To 

prevent     this,     every 


\y/^ 


mortise  forming  a  re- 
ceptacle for  water 
should  be  provided 
with  a  drip  hole  |  inch 
in  diameter,  bored  with 
a  downward  inclina- 
tion from  the  bottom 
of  the  mortise  to  the 


Fig.  669. 
Fig.  568. 

outside  of  the  timber.     Two  methods  of  boring  drip  holes 
are  shown  in  Figs.  508  and  5G9. 

There  are  usually  four  posts  to  a  bent;  two  vertical,  or 
plumb,  posts,  and  two  inclined,  or  batter,  posts.  The  stand- 
ard dimensions  of  trestle  posts  are  12  inches  by  12  inches, 
though  other  dimensions  are  sometimes  used.     The  plumb 


RAILROAD    STRUCTURES. 
TABLE    44. 


1183 


LENG 

rTH 

OF 

BATTER 

POSTS. 

BATTER 

3  IIV.  PER 

FOOT. 

Length 

of  Stick. 

Length 

of  Stick. 

Distance 
Between 

Distflr*'"*  1 

Shr 

ul- 

St 

ck 

With 

Betw« 

en 

She 

ul- 

Stick 

With 

Cap. 

ind 

der  to 

with 

Two 

Cap  and  1 

der  to 

with 

Two 

Sil 

I. 

Shoul- 

Square 

6-in. 

Sill 

Shoul- 

Square 

5- 

n. 

der. 

Ends. 

Ten 

ons. 

der. 

Ends. 

Tenons. 

ft. 

in. 

ft. 

in. 

ft. 

in. 

ft. 

in. 

ft. 

in. 

ft. 

in. 

ft. 

in. 

ft. 

in. 

3 

0 

3 

1 

3 

4 

4 

2 

23 

23 

Si 

23 

IH 

24 

9i 

3 

6 

3 

n 

3 

lOi 

4 

8i 

23 

6 

24 

2f 

24 

H 

25 

3i 

4 

4 

n 

4 

4i 

5 

2i 

24 

24 

8| 

24 

Hi 

25 

n 

4 

6 

4 

n 

4 

lOf 

5 

8f 

24 

6 

25 

3 

25 

6 

26 

4 

5 

5 

n 

5 

H 

6 

n 

25 

25 

H 

26 

Oir 

26 

lOi 

5 

6 

5 

8 

5 

11 

6 

9 

25 

6 

26 

m 

26 

H 

27 

4| 

6 

6 

2i 

6 

5i 

7 

3i 

26 

26 

n 

27 

Of 

27 

lOf 

6 

6 

6 

8f 

6 

llf 

7 

9f 

26 

6 

27 

3f 

27 

6f 

28 

4i 

7 

7 

2i 

7 

H 

8 

H 

27 

27 

10 

28 

1 

28 

11 

7 

6 

7 

81 

7 

llf 

8 

n 

27 

6 

28 

4i 

28 

n 

29 

H 

8 

8 

3 

8 

6 

9 

4 

28 

28 

10| 

29 

If 

29 

llf 

8 

6 

8 

9i 

9 

Oi 

9 

lOi 

28 

6 

29 

4i 

29 

7i 

30 

H 

9 

9 

H 

9 

n 

10 

H 

29 

29 

lOf 

30 

1* 

30 

llf 

9 

6 

9 

H 

10 

Oi 

10 

10^ 

29 

6 

30 

H 

30 

n 

31 

5i 

10 

10 

3f 

10 

H 

11 

4f 

30 

30 

11 

31 

2 

32 

0 

10 

6 

10 

H 

11 

Oi 

11 

10| 

30 

6 

31 

H 

31 

Si 

32 

H 

11 

11 

4 

11 

7 

12 

5 

31 

31 

m 

32 

^ 

33 

Oi 

11 

6 

11 

m 

12 

u 

12 

Hi 

31 

6 

32 

H 

32 

8f 

33 

6f 

12 

12 

^ 

12 

n 

13 

H 

32 

32 

m 

33 

2| 

34 

Oi 

12 

6 

12 

lOf 

13 

If 

13 

IH 

32 

6 

33 

6 

33 

9 

34 

7 

13 

13 

4| 

13 

n 

14 

51 

33 

34 

Oi 

34 

3i 

35 

li 

13 

6 

13 

11 

14 

2 

15 

33 

6 

34 

6| 

34 

9f 

35 

n 

14 

14 

H 

14 

8i 

15 

6i 

34 

35 

Oi 

35 

3i 

36 

H 

14 

6 

14 

111 

15 

2| 

16 

Of 

34 

6 

35 

6f 

35 

9f 

36 

7f 

15 

15 

U  1  15 

8i 

16 

H 

35 

36 

0| 

36 

3i 

37 

li 

15 

6 

15 

111 

16 

2i 

17 

Of 

35 

6 

36 

n 

36 

m 

37 

8i 

16 

16 

H 

16 

8J 

17 

6i 

36 

37 

n 

37 

H 

38 

2i 

16 

6 

17 

0 

17 

3 

18 

1 

36 

6 

37 

n 

37 

lOi 

38 

Si 

17 

17 

H 

17 

H 

18 

n 

37 

38 

If 

38 

4| 

39 

2f 

17 

6 

18 

Oi 

18 

3* 

19 

n 

37 

6 

38 

n 

38 

lOi 

39 

8i 

18 

18 

6| 

18 

H 

19 

n 

38 

39 

2 

39 

5 

40 

3 

18 

6 

19 

Oi 

19 

H 

20 

n 

38 

6 

39 

Si 

39 

Hi 

40 

9i 

19 

19 

7 

19 

10 

20 

8 

39 

40 

2f 

40 

H 

41 

3f 

19 

6 

20 

u 

20 

H 

21 

2i 

39 

6 

40 

8| 

40 

llf 

41 

H 

20 

20 

'1 

20 

lOf 

21 

8f 

40 

41 

2| 

41 

5i 

42 

H 

20 

6 

21 

u 

21 

H 

22 

2i 

40 

6 

41 

9 

42 

0 

42 

10 

21 

21 

n 

21 

m 

22 

8f 

41 

42 

3i 

42 

H 

43 

4i 

21 

6 

22 

n 

22 

H 

23 

2^ 

41 

6 

42 

n 

43 

Of 

43 

lOf 

22 

22 

8i 

22 

IH 

23 

H 

42 

43 

3i 

43 

^ 

44 

4i 

22 

6 

23 

2i 

23 

H 

24 

3i 

42 

6 

43 

91 

44 

Oi 

44 

lOf 

1184 


RAILROAD    STRUCTURES. 


posts  should  be  spaced  from  4  to  5  feet  between  centers,  and 
the  batter  posts  11  feet  from  center  to  center  at  the  top. 
The  inclined  posts  should  have  a  batter  of  3  inches  to  the 
foot.  This  gives  a  broad  base,  adding  considerably  to  the 
stiffness  and  stability  of  the  structure.  It  is  poor  economy 
to  stint  the  dimensions  of  trestle  timbers.  It  is  far  better  to 
have  an  excess  of  strength  than  a  lack  of  it,  and  the  addition 
of  one  or  two  inches  to  any  dimension  involves  but  a  slight 
increase  in  cost  and  makes  safety  certain. 

Table  44  gives  the  length  of  batter  posts  for  different 
heights  at  an  inclination  of  3  inches  per  foot. 

The  first  column  gives  the  vertical  height  of  the  bent 
from  top  of  sill  to  base  of  cap.  The  second  column  gives 
the  length  of  the  post  as  measured  along  either  edge  after  the 
end  is  cut  to  the  proper  angle.  The  third  column  gives  the 
length  of  the  timber  with  square  ends  required  to  cut 
the  post,  and  the  fourth  column  the  length  of  stick  required 
to  give  a  tenon  5  inches  long  on  both  ends  of  post. 

The  table  is  used  as  follows:  The  height  of  a  bent  from 
base  of  sill  to  top  of  cap  is  25  ft.,  the  cap  and  sill  are  each 
12  in.  by  12  in. ;  what  length  of  timber  is  required  for  posts 
to  batter  3  in.  to  the  foot  and  give  a  5-in.  tenon  at  both 
ends  ?  Deducting  2  ft.  from  25  ft.,  the  total  height  of  bent, 
we  have  23  ft.,  the  distance  between  cap  and  sill.  Referring 
to  the  table  we  find  in  the  fourth  column  opposite  23  ft., 
24  ft.  9^  in.,  the  required  length  of  the  posts. 


1750.     Batter  post  templates   set  at  the  proper  angle 

are  very  convenient  for  cutting 
the  ends  of  posts.  A  piece  of 
^-inch  hard  wood  board  cut 
to  the  proper  angle  with  a 
1-inch  cleat  fastened  to  the 
edge  of  the  board,  to  fit  against 
the  edge  of  the  batter  post, 
serves  the  purpose  well.  A 
template  of  this  description  is 
Fig.  570.  shown  in  Fig.  570. 


RAILROAD    STRUCTURES. 


1185 


Some  designers  place  the  plumb  and  batter  posts  so  as  to 
touch   each   other  where   they   meet   the   caps  (Fig.  571). 


Fig.  571. 


FIG.  572. 

When  all  the  posts  are  battered,  the  distance  between  them 
at  the  top  is  fixed. 

The  outside  posts  have  a  uniform  batter  irrespective  of 
height,  while  the  inside  posts  change  their  batter  with  each 
change  of  height  (Fig.  572). 

The  caps,  if  solid,  should  be  of  not  more  than  12-in.  by 
r2-in.  timber.  In  a  majority  of  cases  10-in.  by  10-in.  tim- 
ber would  serve  equally  well,  often  insuring  better  timber 
and  resulting  in  considerable  saving  of  material.  There  are 
several  different  ways  of  joining  the  sills,  posts,  and  caps 
together,  but  only  three  are  iii  general  use,  viz.,  by  mortise 
and  tenon,. by  drift  bolts,  and  by  dowels. 

A  tenon  3  inches  thick,  8  inches  wide,  and  5  inches  long  is 
a  good  size.  The  mortise  should  be  about  ^  inch  deeper 
than  the  length  of  the  tenon  and  well  finished,  so  that  the 
tenon  will  fit  snugly.  In  boring  the  hole  for  the  treenail, 
the  same  precaution  should  be  taken  with  framed  bents  as 
with  pile  bents.  All  mortises  so  placed  as  to  hold  water 
should  be  provided  with  drip  holes. 

1751.  The  use  of  drift  bolts  in  connecting  cap  and  sill 
with  posts  is  shown  in  Fig.  573,  and  dowel  connections  in 
Fig.  574. 

Two  drift  bolts  are  required  to  fasten  a  post  to  the  sill 
and  one  to  secure  it  to  the  cap.  A  hole  must  be  bored 
for  each  drift  bolt,  two  sizes  of  holes  being  used.  The  first 
hole  is  slightly  smaller  than  the  drift  bolt,  the  second  hole 
still  smaller.     The  drift  bolts  used  for  these  connections  are 


118G 


RAILROAD   STRUCTURES. 


either  of  square  or  round  iron.  If  square,  f  inch  will 
answer,  or  iron  of  equivalent  weight,  if  round.  Dowels  are 
usually  of  f-inch  round  iron. 


X 


Fig.  573. 


Fig.  574. 


Split  caps  and  sills  are  preferred  on  some  roads,  and 
when  used,  the  connections  with  the  posts  are  made  similar 
to  split  cap  connections  of  pile  trestles  (see  Fig.  561). 

It  is  customary  to  notch  both  cap  and  sill  at  the  post 

joints.  Both  square 
and  beveled  notches 
are  employed  (see 
Figs.  575  and  576), 
Fig.  575.  Fig.  576.  though      the      former 

(Fig.  575)  is  to  be  preferred. 

Bents  should  be  uniformly  spaced,  the  distance  between 
centers  of  bents  being  from  12  to  16  feet,  depending  upon 
the  character  and  cost  of  timber.  Spans  from  12  to  14  feet 
are  most  common. 


FLOOR  SYSTEM. 
1752.     Corbels. —  Corbels   are    placed    lengthwise  the 
stringers  and  between  them  and  the  caps.     They  are  not 


Fig.  577. 


Fig  578 


favored  by  the  best  designers,  and  do  not  appear  in  most 
trestles  of  recent  construction.     Corbels  are  usually  frona 


RAILROAD   STRUCTURES. 


1187 


4  to  8  feet  long,  extending  equal  distances  each  side  of  the 
cap.  They  are  usually  notched  down  on  the  caps,  and  often 
doweled  to  them.  The  stringers  are  bolted  to  the  corbels, 
which  virtually  shorten  the  span,  so  that  lighter  stringers 
may  be  used  with  corbels  than  without  them.  If,  however, 
the  cost  of  the  corbels  was  expended  in  increasing  the  size 
of  the  stringers,  an  equally  strong  and  considerably  simpler 
structure  would  be  the  result.  Two  common  types  of 
corbels  are  shown  in  Figs.  577  and  578. 

1753.  Stringers. — A  stringer  is  usually  placed  direct- 
ly beneath  each  rail,  and  instead  of  a  single  piece  of  timber, 
it  should  be  composed  of  two  or  more  smaller  pieces  which 
combined  possess  the  requisite  strength.  Smaller  sizes  of 
timber  are  less  expensive  and  less  liable  to  conceal  dama- 
ging defects.  *  These  pieces  should  be  separated  from  each 


^  \  '-0'  J    „„„___ 
.1  \^   ^^ 


Fig.  579. 


Fig, 


Fig.  581. 


Fig.  582. 


Fig.  583. 


Fig.  584. 


Other  either  by  cast-iron  separators^  or  by  packing-blocks^  or 
both.  The  distance  apart  at  which  stringers  are  placed 
varies  widely,  ranging  from  nothing  to  10  or  12  inches.  A 
safe  distance  is  3  inches,  the  space  being  occupied  by  both  a 
separator  and  a  packing-block.  Common  types  of  separators 
are  given  in  Figs.  579  to  584. 

The  prime  object  of  the  separator  is  to  hold  the  stringers 
apart  from  each  other,  and  so  prevent  the  accumulation  of 
moisture,  which  would  soon  induce  decay. 

1754.  Packing-blocks  are  pieces  of  plank  from  4  to 
6  feet  in  length  placed  between  the  stringers  and  over  the 
caps.  They  extend  equally  in  both  directions  from  the  cap, 
and  some  contain  a  notch  which  fits  down  over  the  cap. 
They  serve  to  strengthen  the  connection  between  cap  and 
stringer,  and,  together  with  the  separators,  maintain  the 
space  between  the  stringers. 


1188 


RAILROAD   STRUCTURES. 


There  are  several  styles  of  packing-blocks,  among  which 
are  those  shown  in  Figs.  585,  58G,  and  587.  Of  these  the 
type  shown  in  Fig.  587  is  recommended.     This  block  is  6 


Fig.  585. 


Fig.  586. 


Fig.  587. 


feet  in  length  and  2  inches  in  thickness.  Four  |-inch  bolts 
pass  through  both  stringers  and  packing-block.  Separators 
^  inch  thick  (see  Fig.  579)  are  placed  between  the  stringer 
and  packing-block,  the  stringer  or  packing-bolts  passing 
through  the  separators  and  holding  them  in  place. 

1755.  Wherever  practicable,  the  stringer  should  be 
long  enough  to  cover  two  spans,  so  as  to  break  joints  on  the 
caps.  Some  provision  should  be  made  for  holding  the 
stringers  firmly  in  place.  This  is  usually  effected  by  drift- 
bolting  the  stringers  to  the  caps.  One  objection  to  this 
mode  of  fastening  stringers  is  the  great  difficulty  in  remov- 
ing the  bolts  when  repairs  are  to  be  made.  To  obviate  this 
difficulty,  pieces  of  3-inch  by  12-inch  plank  of  such  length 
as  to  give  to  the  stringers  the  proper  spacing  are  placed  be 
tween  the  stringers,  being  fastened  to  the  caps  by  spikes  or 
lag-screws.  These  pieces  of  plank  are  called  spreaders,  and 
they  are  already  much  in  favor. 

1  756.     Stringer  Joints. — There   are  many   different 
styles   of    stringer    joints   employed    on    American    roads, 


d 


^ 


3 


^fe 


1 


nif^ 


I 


Fig.  688.  Fig.  580. 

among  which  those  shown  in  Figs.  588  to  591  have  especial 
merit. 


RAILROAD    STRUCTURES. 


1189 


The  joint  shown  in  Fig.  588  is  especially  recommended- 
It  is  simple,  strong,  and  withstands  decay.  In  case  the  sup- 
ports should  settle  so  as  to  practically  double  the  span,  the 

n 


^    »  I   I?    f- 


.^44Tr1 


^xr 


3    E 


"n 


Fig.  590. 


Fig.  591. 


joint  is  SO  constructed  as  to  best  resist  this  strain.  Any 
tendency  to  settle  is  at  once  counteracted  by  the  packing- 
bolts,  which  must  either  break  or  split  the  stringer  before 
the  joint  can  fail.  The  strain  is  greatest  on  the  lower  bolts, 
which  are  placed  furthest  from  the  joint,  where  they  are 
least  likely  to  split  the  stringer.  This  joint  would  be  im- 
proved by  placing  a  separator,  like  that  shown  in  Fig.  579, 
between  each  stringer  and  the  packing-block.  This  would 
make  the  space  between  the  stringers  3  inches. 

To  prevent  longitudinal  movement,  stringers  must  be 
either  notched  down  one  inch  on  the  caps  or  drift-bolted 
to  them.  All  packing-bolts  should  be  long  enough  to 
receive  a  cast  wasJier  under 
both  head  and  nut.  The 
difficulty  of  removing  drift- 
bolts  when  making  repairs 
has  already  been  mentioned. 
By  notching  down  the  string- 
ers on  the  caps,  and  by  placing 
a  spreader  a  between  them 
(see  Fig.  502),  all  lateral 
movement  is  prevented.  The 
spreaders  are  fastened  to  the 
caps  either  by  lag  -  screws  or  fig.  tm. 


1190 


RAILROAD    STRUCTURES. 


by  spikes.  By  notching  down  the  ties  1  inch  on  the  stringers 
(see  b^  Fig.  592),  the  spacing  of  the  stringers  is  maintained, 
and  the  ties  held  rigidly  in  place. 

1757.  Size  of  Stringers. — The  size  of  the  stringer 
pieces  in  section  will  depend  upon  the  length  of  the  span 
and  the  character  of  the  traffic.  Two  is  the  number  of 
pieces  generally  used.  They  should  be  of  sufficient  dimen- 
sions to  carry  the  heaviest  train  load  without  any  consider- 
able deflection.  A  stringer  more  used  on  American  roads 
than  all  others  has  the  following  dimensions :  Width,  8  inches ; 
depth,  IG  inches,  and  length  varying  from  2-4  to  28  feet. 
Each  rail  is  supported  by  two  such  pieces,  making  four  for 
a  complete  span.  Yellow  or  Southern  pine  is  generally 
used,  though  white  pine,  Oregon  pine,  spruce,  or  even  hem- 
lock of  these  dimensions,  if  sound,  will  carry  any  train  load 
ordinarily  hauled  on  American  lines.  Dimensions  of  track 
stringers  used  on  the  Pennsylvania  Railroad  are  given  in 
Table  45. 

TABLE    45. 


TRESTLE    STRINGERS,   PENNSYLVANIA    RAILROAD 
STANDARD. 


Dimensions  of  Stringers. 


Clear  Span. 

Number  of  Pieces 
under  Each  Rail. 

Width  of  Each 
Piece. 

Depth  of 
Stringers. 

10  ft. 

2 

8  in. 

15  in. 

12  ft. 

2 

8  in. 

IG  in. 

Uft. 

2 

10  in. 

17  in. 

IG  ft. 

3 

8  in. 

17  in. 

1758.  A  jack-stringer  composed  of  a  single  piece, 
and  shown  at  c  in  Fig.  592,  is  often  placed  near  the  ends 
of  the  ties  and  directly  beneath  the  guard-rail,  the  object  of 
which  is  to  afford  additional  support  to  the  ties  in  case  of 


RAILROAD   STRUCTURES. 


1191 


derailment.  Without  this  support  the  ties  are  likely  to  be 
broken  by  a  derailed  engine,  and  a  total  wreck  follow,  while 
with  it,  providing  the  guard-rail  holds,  the  engine  and  train 
are  likely  to  remain  on  the  trestle.  This  greatly  increases 
the  factor  of  safety.  The  jack-stringers  should  reach  over 
two  spans,  breaking  joints  alternately,  and  be  drift-bolted 
to  the  caps.  The  ends  of  the  stringers  should  abut  against 
each  other,  though  there  are  a  few  instances  to  the  contrary. 

1759.     Ties. — Trestle   ties  vary   in   both    section    and 
length.     A  good  size  is  7  in.  by  8  in.  by  12  ft.  in  length. 


-«# 


3 


iS 


nnnnnnrin 


yi5- 


'-^ 


z 


qrike 


8L(tg-screw 


Fig.  593. 


"^Ij  lj  u  u  u  u  u  G 

8  Lug  screw 


Fig.  594. 


¥^ 


This  length  provides  for  a  jack-stringer.  Many  ties  are 
only  9  feet  in  length,  while  others  are  10  feet.  They  are 
spaced  from  12  to  24  inches  between  centers,  though  15  inches 


}Bolt 


ixl3 Boat  spike 

n  n  n  n  n  nxni  ^ 


^lll^^llMjwfe^     rSi,"^"^"^ 


Fig.  595. 


Fig.  596. 


should  be  the  limit.     The  reason  for  placing  them  close 
together  is  that,  in  case  of  derailment,  ties  closely  spaced 


1192  RAILROAD    STRUCTURES. 

afford  a  fairly  continuous  support  for  the  car  wheels,  es- 
pecially the  driving  wheels,  while  those  widely  spaced  allow 
the  wheels  to  drop  between,  and  the  ties  are  torn  up,  and  a 
wreck  is  likely  to  follow.  On  some  roads,  none  of  the  ties  are 
fastened  to  the  stringers;  on  others,  every  fifth,  or  even 
every  other,  tie  is  fastened,  spikes  or  lag-screws  being  gen- 
erally used  for  the  purpose.  Dowels  are  used  for  tie  fasten- 
ings, but  only  in  a  limited  way,  the  only  important  road 
employing  them  being  the  Louisville  and  Nashville  Railroad 
(Fig.  597).  Four  different  standard  floor  systems  are  given 
in  Figs.  593  to  596,  showing  the  arrangement  and  mode  of 
fastening  cross-ties.   In  the  Pennsylvania  standard,  the  wide 

spaces  between  the  ties  are 
a  serious  objection,  as  in 
case  of  derailment  it  ren- 
ders wreck  almost  certain. 
The  dimensions  and  arrange- 
^"'^-  °^-  ment  of  ties  in  Fig.  594  are 

especially  recommended.  Ties  should  always  be  notched 
down  1  inch  over  the  stringers.  Notching  prevents  any 
lateral  movement  and  strengthens  the  floor  system. 

1760.  Guard-Rails. — Guard-rails  are  an  important 
part  of  the  trestle.  Their  purpose  is  twofold,  viz.,  first,  to 
prevent  a  train  from  leaving  the  bridge  in  case  of  derail- 
ment, and,  second,  to  maintain  the  spacing  of  the  ties  and 
add  weight  and  strength  to  the  floor  system.  Where  a 
jack-stringer  is  used,  the  guard-rail  is  placed  directly  above 
it.  Guard-rails  should  be  notched  down  upon  the  ties, 
usually  1  inch,  and  fastened  to  them  either  with  bolts  or 
lag-screws.  Guard-rails  in  section  should  be  not  less  than 
G  by  8  inches,  the  length  depending  on  the  available  supply, 
but  no  length  under  16  feet  should  be  used.  Commonly  the 
guard-rails  and  cross-ties  are  of  the  same  sized  timber,  7  by 
8  inches  being  a  standard  size,  the  lengths  running  from  20 
to  24  feet.  They  are  spliced  in  a  variety  of  ways.  Various 
forms  of  splices  are  shown  in  Figs.  598  to  601.  The  halved 
joint  (Fig.  598)  is  recommended  as  simple  and  effective. 


RAILROAD    STRUCTURES.  ll'J3 

Joints  should  come  directly  over  a  tie  and  be  broken,  i.  e., 
a  joint  on  one  guard-rail  should  be  on  line  with  the  middle 
point  of  the  opposite  guard-rail.  Each  joint  should  be 
fastened  with  either  a  bolt  or  a  lag-screw.  Bolts  are  to  be 
much  preferred  to  lag-screws  for  fastening  guard-rails  to 
ties.  Lag-screws  tear  the  fiber  of  the  wood,  and  form 
cavities  which  hold  moisture  and  induce  decay.  The  best 
plan  is  to  bolt  every  fourth  or  fifth  tie  to  the  guard-rail,  and 


r  I    {    uuu   Trn 


2    )■  ,^o»'~'  ^     ^«=5=i^  ^^  ^=a=^ 


Fig.  598.  Fig.  599.  Fig.  600.  Fig.  601.       Fig.  602.    Fig.  603. 

spike  the  remaining  ties  with  10-inch  boat  spikes.  A 
puncJied  washer  should  be  put  under  the  head  of  each  lag- 
screw.  It  is  a  waste  of  time  and  an  injury  to  the  timber  to 
countersink  the  heads  of  bolts  or  lag-screws.  The  holes 
form  receptacles  for  water,  which  soon  induces  decay.  A 
3  to  3^-inch  cast  washer  should  be  placed  under  the  head  and 
nut  of  each  bolt,  the  nut  being  placed  up  so  as  to  make 
inspection  and  repairs  easy. 

1761.  The  ends  of  the  guard-rail  should  be  beveled,  as 
shown  in  Fig.  602  or  G03.  The  guard-rails  should  extend 
from  20  to  30  feet  from  the  trestle  on  to  the  embankment. 
They  should  be  flared  outwards  so  that  at  their  extremities 
they  will  be  from  3  to  4  feet  from  the  rails.  The  object  of 
flaring  the  guard-rails  is  to  assist  any  car  which  may  have 
been  derailed  on  the  embankment  in  passing  the  trestle  in 
safety  (see  Fig.  604).  On  some  roads,  in  addition  to 
these  flaring  guards,  bumping  posts  are  placed  near  the 
end  of  the  embankment,  but  their  value  is  not  generally 
admitted. 

An  additional  safeguard,  and  one  in  general  use  on  some 
lines,  is  an  inner  guard-rail  of  the  same  section  as  the  main 
rail,  placed  2^  inches  inside  the  rail.  Objection  is  made  by 
some  to  this  form  of  guard-rail  on  the  ground  of  its  forming 


1194 


RAILROAD    STRUCTURES. 


a  lodgment  for  detached  pieces  of  the  truck,  such  as  brake 
shoes,  box  lids,  etc.,  causing  the  wheels  to  mount  the  rails. 
The  tendency  of  wheels  to  mount  the  wooden  guards  may  be 


cr-ilj  iy  iiijfj  ill  ij 


Fig.  604. 

prevented  by  fastening  a  strip  of  angle  iron  on  the  upper 
inside  edge  of  the  guard-rail. 

1762.  Fastening  Down  Floor  System. — There 
are  several  different  methods  of  fastening  the  floor  system 
down  to  the  bents,  some  of  which  have  already  been  men- 
tioned. The  method  generally  adopted  is  to  drift-bolt  the 
Hs-1  r^  ,\H  stringersto  the  caps  (Fig. G05). 

The    only    objection    to    this 
method    has   already    been 
/- Ul  UL  stated,   viz.,   the  difficulty    of 

removing  the  bolts  when 
making  repairs.  This  mode 
of  fastening  the  floor  system 
has  the  merits  of  simplicity 
mJ  m  \A\     and  security,  and  is  more  used 

^''<^-^<'5-  than    all    others.     Another 

method  is  to  bolt  the  stringers  to  the  caps,  in  which  case  the 
posts  must  be  so  spaced  as  to  allow  the  bolt  to  pass  through 
the  cap.  On  some  roads  the  stringers  are  not  fastened  to 
the  caps,  the  weight  of  the  floor  system  being  depended 


RAILROAD    STRUCTURES. 


1195 


upon  to  hold  them  down.  In  such  cases  the  stringers  must 
be  notched  down  1  inch  upon  the  caps  and  spreaders,  as 
shown  in  Fig.  592,  used  to  prevent  lateral  movement. 


Bents 


Fig.  606. 


BRACING. 
1763.     Sway-Bracing. — Pile  or  framed  bents  under 
10  feet  in  height  seldom  require  any  sway-bracing, 
from  10  to  20  feet  in  height  require  a 
single  X  brace   of  3-inch  by   10-inch 
planks  extending  diagonally  from  the 
upper  corner  of  the  cap  to  the  foot  of 
the    opposite    pile   or    to    the    outside 
corner  of    the    sill,  if  a  framed  bent 
(see  Fig.  606).     For  bents  from  20  to 
40  feet  in  height,  two  X  braces  separa- 
ted by  3-inch  by  10-inch  horizontal  planks  spiked  to  both  sides 
of  the  bent,  as  shown  in  Fig.  607,  afford  ample  bracing.   There 

are  two  methods  of  fastening 
the  sway-braces,  both  in  gen- 
eral use.  In  one,  the  sway 
braces  are  fastened  to  the 
piles  or  posts  with  f-inch 
bolts  and  cast  washers,  as 
shown  in  Fig.  606;  in  the 
other,  they  are  spiked  with  ^- 
inch  by  8-inch  boat  spikes. 
Bolt  fastenings  may  be  easily 
removed  without  damaging 
the  braces,  which  may  be 
used  a  second  time,  if  not 
^'"'"-  ^~-  decayed.       Spikes,     on     the 

other  hand,  are  difficult  to  draw,  and  sway-braces  are  often 
split  or  broken  in  removing  them  from  the  bents.  However, 
second-hand  trestle  material  is  of  little  value,  and  as  spikes 
are  a  sure  fastening  and  cheaper  and  more  expeditious 
than  bolts,  they  are  to  be  recommended. 

When   the   piles  of  a  bent    are   out    of   line  so  that   the 
sway-brace  can  not  lie  flat,  they  should  either  be  hewn  so  that 


1196  RAILROAD    STRUCTURES. 

the  sway-brace  will  come  in  direct  contact  with  every  pile  or 
post,  or  a  packing  piece  of  the  necessary  thickness  should  be 
placed  under  the  sway-brace  to  give  it  a  full  bearing  on  the 
bent. 

1764.  Counter  Posts.  — Framed  bents  exceeding  a 
height  of  30  feet  are  frequently  stiffened  by  counter  posts  a  h 
and  c  d,  shown  in  Fig.  025,  Art.  1 792,  in  the  section  on 
Standard  Trestles.  Counter  posts  require  the  dividing  up  of 
the  bent  into  two  or  more  stories  by  means  of  an  intermediate 
sill  cf.  They  are  generally  employed  in  high  work  where 
two  and  sometimes  three  sets  of  counters  are  used. 

1 766.  Longitudinal  Bracing. — This  form  of  bracing 
is  employed  in  various  ways — some  bracing  every  bay  or 
span,  others  every  third  or  fourth  bay.  In  some  trestles 
the  bracing  is  placed  diagonally,  in  others  horizontally, 
while  some  employ  both  forms. 

Fig.  623,  Art.  1 790,  under  Standard  Trestles,  shows  the 
laced  iovm.  of  longitudinal  bracing  as  employed  by  the  Penn- 
sylvania Railroad..  The  caps  and  sills  are  chamfered,  and  the 
braces  cut  to  fit  them,  as  shown  in  the  detail  at  A.  The 
braces  are  fastened  to  both  cap  and  sill  by  heavy  cut  spikes. 

1766.  Lateral  Bracing. — Lateral  bracing,  shown  at 
a  b  m  Fig.  G2G,  Art.  1793,. in  section  on  Standard  Trestles, 
adds  much  to  the  stiffness  of  a  structure.  These  braces  are 
usually  of  G-in.  by  6-in.  timber,  bolted  together  at  their  in- 
tersection c  with  either  #-in.  or  ^-in.  bolts.  They  are  slightly 
notched  into  the  caps,  to  which  they  are  fastened  with  heavy 
cut  spikes.  They  contribute  much  towards  keeping  the 
track  in  line,  and  serve  to  a  considerable  extent  the  purpose 
of  longitudinal  bracing.  Whatever  the  style  of  bracing 
employed,  it  must  be  borne  in  mind  that  the  effectiveness 
of  bracing  depends  largely  upon  the  thoroughness  with  which 
it  is  fastened  to  the  parts  to  be  strengthened.  Sway-bracing 
is  usually  fastened  to  the  cap  and  sill  with  f-in.  bolts,  and 
spiked  to  the  posts  or  piles  with  boat  spikes.  Diagonal 
braces,  especially  those  framed  or  notched  into  the  bent 
timber,  are  frequently  found  loose  and  ineffective.     When 


RAILROAD    STRUCTURES. 


1197 


Fig.  C08. 


spiked  or  bolted  to  place,   they  should  fit  snugly  and  be  at 
least  slightly  strained. 

1767.  Trestles  on  Curves. — Wherever  possible, 
curved  trestles  should  be  avoided.  The  additional  stress  due 
to  the  centrifugal  force  of  ^  ^-w— ^-9- 

heavy  trains  at  high' speed 
is  a  severe  tax  upon  a 
structure,  and  the  locating 
engineer  should,  if  pos- 
sible, so  modify  his  line  as 
to  place  all  trestles  on 
tangents.  Circumstances,  however,  sometimes  render  the 
curved  trestle  a  necessity,  in  which  case  the  outer  posts 
vy^f  a.      g^  INitch  must    have    an    increased 

batter  and  the  outer  rail  its 
proper  elevation. 

There  are  various  meth- 
ods of  elevating  track  on 
curved    trestles,    three   of 
Fig.  609.  which  are  shown    in  Figs. 

608,  609,  and  610.  In  Fig.  608  the  elevation  is  effected  by 
cutting  off  the  piles  or  framing  the  posts  to  such  lengths  as 
will  afford  the  requisite 
elevation.  This  is  the  sim- 
plest and  easiest  method  of 
elevating  the  outer  rail  of  a 
trestle.  There  are  no  shims 
to  get  out  of  place  or  need  ^y 
renewing,  and  there  is  no 
increase  in  cost  above  that 
of   a  trestle  on  a  straight  line. 

In  Fig.  609  the  outer  rail  is  elevated  by  means  of  a  shim  /", 
which  is  placed  under  the  rail  and  fastened  to  the  tie  with 
cut  spikes.  The  weak  point  in  this  mode  of  elevating  the 
outer  rail,  aside  from  the  cost  of  making  and  fastening  the 
shims,  is  the  accumulation  of  moisture  under  the  shims, 
which  induces  their  decay  and  the  decay  of  the  ties  also. 


Fig.  CIO. 


1198 


RAILROAD    STRUCTURES. 


In  Fig.  GIO  the  elevation  is  effected  by  cutting  away  a 
portion  of  the  cap  at  a  to  an  amount  equal  to  the  required 
elevation.  The  stringers  are  then  placed  in  a  horizontal 
position,  as  shown  in  the  figure,  and  the  notches  in  the  ties 
beveled  so  as  to  fit  the  top  of  the  stringers.  In  pile  bents, 
the  caps  are  usually  drift-bolted  to  the  piles,  and  in  framed 
bents  the  connection  is  usually  made  with  mortise  and  ten- 
on. In  all  three  methods,  the  stringers  are  drift-bolted  to 
the  caps.  In  Figs.  G08  and  009,  the  jack-stringers  a  and  b 
add  considerable  to  the  stability  of  the  structures,  and  are 
an  additional  safeguard  in  case  of  derailment.  The  eleva- 
tion of  the  outer  rail  in  each  case  is  3  inches,  and  the  degree 
of  the  curves  6  degrees.  Both  posts  or  piles  c^  d  on  the  out- 
side of  the  curve  are  battered,  the  outside  one  at  a  batter  of 
4  inches  to  the  foot,  and  the  next  inside  2  inches  to  the 
foot.  On  the  inside  of  the  curve,  only  the  outside  posts  or 
piles  e  of  the  bent  are  battered,  and  at  the  usual  batter  of  3 
inches  to  the  foot.  If  the  trestle  is  a  high  one,  it  should  be 
strengthened  by  additional  bracing. 


IRON   DETAILS. 


1768. 


trestle   building,    viz., 


Spikes. — There  are  two  kinds  of  spikes  used  in 
cut  spikes  (Fig.  Oil),  which  are 
formed  like  ordinary  cut  nails  and 
manufactured  in  the  same  way,  and 
boat  spikes  (Fig.  012),  which  are 
forged  from  bars  of  wrought  iron. 
Spikes  of  the  same  length  are  not 
necessarily  of  the  same  weight. 
Slender  spikes  are  not  suited  for 
trestle  building,  as  they  are  liable 
to  bend  and  break,  besides  lacking 
in  holding  power.  Those  having  good  sized  heads  and 
bodies  should  always  be  used.  Steel  spikes  are  to  be  pre- 
ferred to  iron  ones,  as  they  are  tougher  and  stronger. 

Boat  spikes,  shown  in  Fig.   012,  have  strong,  well-formed 
heads,    and   are   chisel  pointed.     They  are   used   to  fasten 


L 


W 


FiG.en.  Fig.  612.        Fig.  613. 


RAILROAD   STRUCTURES. 


1199 


guard-rails  to  ties,  ties  to  stringers,  and  sway-bracing  to  the 
bents. 

Table  46  gives  sizes  and  weights  and  numbers  of  spikes  in 
a  keg  of  100  pounds : 

TABLE  46. 

CUT   SPIKES. 


Length 
in  Inches 


3 

H 

4 
5 


No.  in  Keg 
of  100  lb. 


2,900 
2,100 
1,500 
1,150 
950 


Weight  of 

One  Spike, 

lb. 

Length 
in  Inches 

.0344 

5i 

.0476 

6 

.0667 

H 

.0869 

7 

.1052 

8 

No.  in  Keg 
of  100  lb. 


850 
775 
575 
450 
375 


Weight  of 

One  Spike, 

lb. 


.1176 
.1293 
.1739 
.2222 

.2666 


Table  47  gives  the  lengths  of  the  different  sizes  of  boat 
spikes,  the  approximate  number  of  each  in  a  keg  of  150 
pounds,  and  the  weight  of  each. 

1769.  Drift  Bolts. — Drift  bolts  commonly  resemble 
boat  spikes  in  shape,  but  they  are  much  larger.  The  heads 
are  less  carefully  shaped,  and  often  they  are  used  without 
either  head  or  point,  the  bolts  being  simply  sheared  from 
rods  to  a  proper  length,  and  driven  into  the  holes  bored 
to  receive  them.  The  ordinary  shapes  are  shown  in  Fig. 
613.  For  fastening  12-inch  caps  to  posts  or  piles,  drift 
bolts  of  f-inch  square  or  |-inch  round  iron  and  20  inches 
long  are  commonly  used.  They  should  always  penetrate 
the  last  timber  into  which  they  are  driven  a  sufficient  dis- 
tance to  resist  any  legitimate  pull  or  shock  which  will  be 
placed  upon  them.  Holes  are  always  bored  to  receive  drift- 
bolts.  They  should  be  of  such  size  that,  in  driving,  the 
fibers  of  the  wood  will  fill  all  space  not  occupied  by  the  bolt 
itself. 


1200 


RAILROAD    STRUCTURES. 


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RAILROAD   STRUCTURES. 


1201 


Table   48   gives  the  weight   of   drift-bolts   of    the    sizes 
commonly  used: 

TABLE    48. 


IJVEIGHTS    OF    DRIFT-BOLTS. 


Length  in  Inches. 

Square  Section. 

Round  Section. 

f  in.  sq. 

1  in.  sq. 

f  in.  diam. 

1  in.  diam. 

18 
20 
22 
24 
26 

Lb. 
2.9 
3.2 
3.5 
3.8 
4.1 

Lb. 

5.1 
5.7 
6.2 
6.8 
7.3 

Lb. 
2.3 
2.5 
2.8 
3.0 
3.3 

Lb. 
4.0 
4.4 
4.9 
5.3 
5.8 

1770.  The  main  value  of  drift-bolts  lies  in  their  hold- 
ing power.  A  long  series  of  experiments  by  the  United 
States  Engineer  Corps,  made  while  building  the  St.  Mary's 
Canal  locks,  developed  the  following  results: 

The  mean  of  from  150  to  200  experiments  with  round  and 
square  bolts,  both  smooth  and  ragged,  in  different-sized 
holes,  shows  that  the  resistance  after  having  been  driven 
seven  months  is  10  per  cent,  greater  than  the  resistance 
immediately  after  driving,  the  different  sizes  and  forms 
being  strictly  uniform. 

The  mean  of  150  experiments  under  various  conditions 
shows  that  the  resistance  to  being  drawn  in  the  direction  in 
which  the  bolts  were  driven  is  only  60  per  cent,  of  their 
resistance  to  being  drawn  in  the  opposite  direction;  that  is 
to  say,  the  resistance  to  being  drawn  through  is  only  60  per 
cent,  of  the  resistance  to  being  drawn  back.  The  mean  of 
50  experiments  shows  that  smooth  rods  have  a  greater 
resistance  than  ragged  bolts,  both  to  being  drawn  through 
and  also  to  being  drawn  back;  that  a  moderate  ragging 
reduces  the  holding  power  a  little  more  than  25  per  cent., 
and  an  excessive  ragging  reduces  the  holding  power  more 
than  50  per  cent. 


1202  RAILROAD    STRUCTURES. 

The  best  relation  between  the  diameter  of  the  bolt  and 
that  of  the  hole,  as  determined  by  one  series  of  60  experi- 
ments, shows  that  the  holding  power  of  a  1-inch-round  bolt 
in  a  l^-inchhole  is  greater  than  in  a  ff-inch  or  a  ||-inch  hole, 
the  resistance  in  a  |^|-inch  hole  being  98  per  cent,  and  that 
in  a  f|-inch  hole  being  90  per  cent,  of  that  in  a  [^-inch  hole. 
Another  series  of  35  experiments  makes  the  holding  power 
of  a  1-inch  round  bolt  in  a  ||-inch  hole  greater  than  in  a  |f 
or  a  ||-inch  hole,  the  first  two  being  practically  the  same, 
and  the  last  being  only  85  per  cent,  of  the  first.  For  a 
f-inch  round  bolt  four  experiments  with  each  size  prove  that 
the  holding  power  of  the  bolt  in  a  |f-inch  hole  is  about  one 
quarter  greater  than  in  a  y^-inch  or  a  ^-inch  hole.  For  a 
1-inch  square  bolt,  the  holding  power  in  a  ||^-inch  hole  is  only 
a.  trifle  greater  than  in  a  [f-inch  hole,  and  about  20  per  cent, 
greater  than  in  a  [f-inch  hole,  as  deduced  from  20  to  40 
experiments  for  each  size  of  hole. 

The  holding  power  of  a  1-inch  square  bolt  in  a  f|-inch 
hole  was  practically  the  same  as  for  a  1-inch  round  rod  in  a 
l^-inch  hole.  There  is  25  per  cent,  more  metal  in  the 
square  drift-bolt  and  more  labor  is  required  in  boring  a  ||- 
inch  hole  than  in  boring  a  f^-inch  hole;  hence,  the  round 
drift-bolt  is  25  per  cent,  more  efficient  than  the  square  one. 

In  the  matter  of  pointing  the  bolts,  experiment  goes  to 
prove  that  drift-bolts  with  a  long,  slender  point  have  about 
10  per  cent,  greater  resistance  than  those  with  short,  blunt 
points,  the  conclusion  being  that  the  blunt  points  tear  the 
fiber  of  the  wood,  while  the  slender  points  crowd  it  aside, 
filling  up  the  cavities  of  the  hole,  thereby  increasing  the 
friction  of  the  bolt. 

1771.  no-wels. — In  place  of  drift-bolts,  short  iron 
rods,  either  square  or  round,  called  do>vels,  are  frequently 
used.  They  have  neither  point  nor  head,  but  are  sheared 
from  rods,  care  only  being  taken  to  make  them  straight. 
They  are  frequently  used  to  fasten  caps  to  posts,  posts  to 
sills,  and  ties  to  stringers.  A  common  size  of  dowel  for 
fastening  caps  to  posts  and  posts  to  sills  is  f-inch  round  or 
square  by  8  inches  in  length,  weighing  about  1  pound  each. 


RAILROAD    STRUCTURES. 


1203 


Dowels  of  f-inch  round  iron,  5  inches  in  length,  are  well 
suited  for  fastening  ties  to  stringers. 

The  following  list  gives  the  weight  of  1-inch  lengths  of 
the  various  sizes  of  iron  bars  or  rods  commonly  employed 
in  this  kind  of  work: 


1  in. 

square 

0.2806  lb. 

|in. 

diam.  round 

0.1240  lb. 

I  in. 

diam.  round 

0.2204  1b. 

fin. 

square 

0. 1096  lb. 

Jin. 

square 

0.2149  lb. 

fin. 

diam.  round 

0.0860  lb. 

|in. 

diam.  round 

0.1687  lb. 

i  in. 

square 

0.0701  lb. 

f  in. 

square 

0.1579  lb. 

i  in. 

diam.  round 

0.0551  lb. 

1772.  Bolts. — Bolts  for  holding  the  stringer  pieces 
together,  fastening  the  braces,  guard-rails,  etc.,  are  com- 
monly of  f-inch  round  iron,  their  lengths,  of  course,  de- 
pending upon  the  purpose  for  which  they  are  to  be 
used.  The  bolt  heads  should  be  well  formed,  and 
of  good  weight,  and  the  threads  right-handed  and 
well  cut. 

&  Bolt  heads  are  of  three  forms — button  heads,  flat 

■      '^    countersunk  heads,  and  the  ordinary  square  heads 

Fig.  614.    (Fig-  614).      Square  nuts  with  a  thickness  equal  to 

the  diameter  of  the  bolt  and  length  of  side  equal  to  twice 

the    diameter   of   the    bolt   are   the   best.     The    outer  top 

corners  of  both  head  and  nut  should  be  chamfered. 

A  cast-iron  washer  from  3  to  3^  inches  in  diameter  should 
be  placed  under  the  head  and  nut  of  all  bolts.  Holes  of 
y*^  inch  less  diameter  than  the  bolts  are  bored  through  the 
timber  to  receive  the  bolts  to  insure  a  close  fit. 

Table  49  gives  sizes  and  weights  of  bolts,  and  though 
not  exact,  owing  to  the  varying  weights  of  heads,  is  amply 
close  for  approximate  estimates. 

In  ordering  bolts,  the  term  grip^  as  sometimes  employed, 
signifies  the  total  thickness  of  the  material  to  be  held 
together;  in  other  words,  the  distance  between  the  inside 
faces  of  washers. 

1773.  Lag-Screws. — A  lag-screw  is  a  large  wood 
screw  which  serves  in  place  of  a  bolt.     The  head  is  shaped 


1204 


RAILROAD    STRUCTURES. 


TABLE  49. 


APPROXIMATE    WEIGHT   OF   BOLTS   IN    POUNDS,    WITH 
SQUARE  HEADS  AND  NUTS,  INCLUDING   BOTH. 

Length 

Under  Head 

in  Inches. 

Diameter  in  Inches. 

i 

f 

f 

1 

1 

6 

0.59 

1.01 

7 

0.G4 

1.10 

8 

0.70 

1.19 

9 

0.75 

1.27 

10 

0.81 

1.3G 

2.10 

3.05 

4.23 

11 

0.8G 

1.44 

2.22 

3.22 

4.45 

12 

0.92 

1.53 

2.35 

3.39 

4.67 

13 

0.97 

1.62 

2.47 

3.55 

4.89 

14 

1.03 

1.70 

2.59 

3.72 

5.11 

15 

1.08 

1.79 

2.72 

3.89 

5.34 

IG 

1.87 

2.84 

4.06 

5.56 

17 

1.96 

2.97 

4.23 

5.78 

18 

2.05 

3.09 

4.40 

6.00 

19 

3.21 

4.57 

6.22 

20 

3.34 

4.74 

6.44 

21 

3.46 

4.90 

6.66 

22 

3.59 

5.07 

6.88 

23 

3.71 

5.24 

7.10 

24 

3.83 

5.41 

7.32 

like  a  bolt  head,  and  an  ordinary  wrench  may  be 
used  in  fastening  the  screw  in  place.  A  hole  of  the 
full  size  of  the  shank  of  the  screw  is  bored  through 
the  first  timber  and  a  much  smaller  one  is  bored  for 
the  balance  of  the  distance  through  which  the  thread 
is  to  pass.  A  wrought  or  punched  washer  cut  from 
sheet  iron  should  be  placed  under  the  head  of 
each  lag-screw.  The  ordinary  form  of  lag-screw  is 
in  Fig.  615, 


Fig.  615. 

shown 


RAILROAD    STRUCTURES. 


1205 


1774.  Washers. — Cast  washers  are  largely  used  in 
trestle  building.  One  should  be  placed  under  the  head  and 
nut  of  every  bolt  used  in  the  structure.  The  more  common 
forms  of  cast  washers  are  shown   in    Fig.    616,   and  their 


dimensions  are  given  in  Table  50.     The  solid  washers  are 
placed  under  the  head  and  the  slotted  washers,  or  those 


TABLE    50. 


DETAILS    OF    CAST-IRON    WASHERS. 


Dimensions 

,  in  Inches. 

Kind,  Fig.  616. 

Diameter 

Diameter 

Diameter 

Thickness. 

of  Back. 

of  Face. 

of  Hole. 

A 

n 

If 

1 

i 

B 

3 

2i 

1 

i 

C 

3 

If 

1 

f 

D 

3 

2 

1 

1 

E 

3 

li 

I 

I 

F 

3 

2 

f 

i 

G 

3i 

2i 

1 

* 

H 

3| 

2i 

li\ 

f 

K 

4 

2 

1 

t 

L 

4f 

2f 

I 

1 
J, 

having  a  second  hole,  under  the  nut.     The  purpose  of  the 
slot,  or  second  hole,  is  to  provide  for  locking  the  nut.    After 


]  20G 


RAILROAD    STRUCTURES. 


the  nut  is  well  tightened,  a  nail  is  driven  in  the  slot  or  hole 
with  the  head  projecting  far  enough  above  the  face  of  the 
washer  to  permit  of  its  being  drawn  with  a  claw  hammer. 
This  effectually  locks  the  nut.  Wrought  washers  may  be 
effectually  locked  by  nicking  the  thread  with  a  center  punch 
after  the  nut  has  been  screwed  home. 

Wrought  washers,  sometimes  called  punched,  are  also 
used  to  a  considerable  extent  in  this  class  of  structures. 
They  are  circular  in  form,  and  are  stamped  out  from  sheet 
iron,  with  a  hole  punched  through  the  center  of  them. 

Table  51  gives  the  dimensions  of  wrought  washers,  and 
the  number  of  each  in  a  keg  of  150  pounds: 

TABLE    51. 


S  halving  the  Average  Number  of  Wrought -Iron  Washers  in 
a  Keg  of  150  pounds  of  each  Standard  Size,  as  Adopted  by 
the  Association  of  Bolt  and  Nut  Manufacturers  of  the 
United  States. 


Size  of 

Thickness, 

Size  of 

Number  in 

Diameter. 

Hole. 

Wire  Gauge. 

Bolt. 

150  Pounds. 

i 

i 

No.  18 

3 

80,000 

1      , 

•    A 

No.  16 

i 

34,285 

1 

A 

No.  16 

i 

22,000 

i 

f 

No.  16 

5 

18,500 

1 

7 

No.  14 

f 

10,550 

H 

i 

No.  14 

1 

7,500 

If 

A 

No.  13 

h 

4,500 

H 

t 

No.  12 

A 

3,850 

If 

H 

No.  10 

1 

2,500 

2 

H 

No.  10 

i 

1,600 

H 

il 

No.     9 

I 

1,300 

H 

ItV 

No.     9 

1 

950 

2f 

li 

No.     9 

li 

700 

3 

If 

No.     9 

li 

550 

H 

H 

No.     9 

If 

450 

RAILROAD    STRUCTURES.  1207 

CONNECTIOlV     WITH     EMBANKMENT— PROTEC- 
TION    AGAINST    ACCIDENTS. 

1 775.  Connection  >vitli  Embankment. — There  ar, 
two  methods,  in  general  use,  of  connecting  a  trestle  with  an 
embankment,  viz.,  by  means  of  a  bank  crib,  and  by  means 
of  a  bank  bent.  In  the  former  method  the  crib  is  usually 
built  of  12-in.  by  12-in.  square  timbers  halved  one  into  the 
other  and  drift-bolted  at  each  intersection  of  the  timbers. 
There  are  several  courses  of  timbers  depending  upon  the 
height  of  the  embankment.  The  building  of  the  crib  should 
be  deferred  until  the  rest  of  the  trestle  is  completed,  so  as 
to  allow  all  possible  time  for  the  settlement  of  the  embank- 
ment. Before  commencing  the  crib,  a  space  of  ample  size 
to  receive  it  should  be  excavated  from  the  end  of  the  em- 
bankment and  the  earth  well  rammed  for  a  foundation  be- 
fore the  timbers  are  put  in  place.  The  correct  elevation  for 
this  foundation  should  be  determined  by  the  engineers,  so 
that  the  top  of  the  crib  may  have  the  proper  elevation  with- 
out hewing  away  any  of  the  timber.  The  timbers  compo- 
sing the  front  of  the  crib,  i.  e.,  the  part  facing  the  trestle, 
should  be  at  least  10  feet  long,  and  those  parallel  to  the 
track  of  equal  length.  The  top  of  the  crib  should  be  fixed 
exactly  at  grade,  so  that  trains  may  pass  from  the  embank- 
ment to  the  trestle,  and  vice  versa,  without  any  jolting. 
Timbers  frequently  vary  ^  inch  in  thickness,  so  that  the 
actual  elevation  of  the  top  of  the  crib  may  vary  1  or  2  inches 
from  the  calculated  one.  This  discrepancy  may  be  readily 
remedied  by  shims,  if  the  top  of  the  crib  is  too  low, 
and  by  notching  down  the  stringer,  if  the  top  is  too 
high.  It  is  well  to  have  the  stringers  extend  back  from 
the  face  of  the  crib  several  feet.  The  bottoms  of  the 
stringers  should  be  kept  from  coming  in  contact  with 
the  earth  of  the  embankment.  This  may  be  prevented 
by  spiking  planks  to  the  crib  timbers  underneath  the 
stringers.  The  stringers  should  be  drift-bolted  to  the 
crib  timbers.      Such   a   connection   between   embankment 


1208 


RAILROAD   STRUCTURES. 


and  trestle   as  we   have  just   described    is   shown   in    Fig. 
017. 


Fio.  617. 


Connection  between  the  embankment  and  the  trestle 
may  be  made  by  means  of  a  bank  bent,  either  of  piles  or 
framed.  This  construction  is  more  favored  than  the  crib 
form  previously  described.  It  consists  of  a  strong  frame  or 
pile  bent  built  into  the  slope  at  the  end  of  the  embankment 
for  the  support  of  the  stringers.  If  piles  are  used,  the  bent 
should  contain  four  piles  deeply  driven  into  the  embank- 
ment, so  that  they  will  not  only  safely  carry  the  train  load, 
but  will  sustain  the  pressure  of  the  back  filling,  which  is 


RAILROAD   STRUCTURES. 


120i> 


carried  up  to  the  base  of  the  stringers.  To  hold  this  piling 
in  place,  the  back  of  the  bent  is  close  planked  with  3 -inch 
or  4-inch  plank.  When  the  bank  bent  is  of  considerable 
height,  struts  of  8-in.  by  8-in.  stuff  should  extend  from 
the  bank  bent  to  the  timbers  of  the  first  trestle  bent,  to 
insure  its  stability.  When  the  bank  bent  is  of  framed  tim- 
ber, special  pains  should  be  taken  to  insure  a  safe  founda- 


FiG.  618. 

tion  for  the  sill.  Sub-sills  of  12-in.  by  12-in.  timber,  laid 
in  trenches,  form  a  good  foundation.  Before  laying  the 
sub-sills,  the  ground  should  be  thoroughly  rammed  to  en- 
sure against  settlement.  This  construction  is  illustrated  in 
Fig.  618. 

1776.  Refuge  Bays. — On  all  trestles  of  a  length  of 
200  feet  or  more,  refuge  bays  should  be  built  where  work- 
men or  track  walkers  can  find  safety  when  overtaken  by  a 
train.  They  consist  of  small  projecting  platforms  supported 
by  ties  which  are  given 
the    additional     length 


4if 


^4-0^ 


/3'a 

'■J  Space 


iM 


—4-9— 


lf^4' 


J 


PS 


necessary  to  include  the 
refuge  bays.  A  refuge 
bay  of  approved  pat- 
tern is  shown  in  Fig. 
619.       On    trestles     of 

a    length   exceeding  fig.  6i9. 

1,000  feet,  every  fourth  refuge  bay  should  be  large  enough 
to  contain  a  hand  car  and  section  gang.  While  repairs 
are  being  made  on  a  trestle,   before  work  is  commenced, 


tnj 


1210  RAILROAD   STRUCTURES. 

the  hand  car,  together  with  all  idle  tools,  should  be  placed 
in  a  refuge  bay,  and  should  remain  there  until  the  work  is 
finished. 

1777.  Foot  Walks. — On  some  roads  it  is  custom- 
ary to  place  between  the  rails  a  foot  walk  of  inch  boards 
from  1  to  2  feet  in  width.  This  is  a  mistake,  in  that 
it  encourages  the  public  to  use  a  trestle  as  a  thorough- 
fare on  account  of  the  ease  in  crossing  it;  it  increases 
the  danger  of  fire,  as  the  walk  forms  a  lodgment  for 
coals  dropped  from  the  fire-boxes  of  the  engines,  and  it 
tends  to  careless  inspection  on  account  of  the  difficulty 
of  reaching  the  parts  of  the  structure  which  are  covered 
by  the  walk. 

1 778.  Fire  Protection. — Every  trestle  should  be  pro- 
vided with  the  means  of  protection  against  fire.  This  is 
sometimes  effected  by  covering  the  tops  of  ties  and  string- 
ers with  sheet  iron.  A  simpler  and  more  effective  protec- 
tion is  afforded  by  water  stored  in  tubs  at  intervals  of 
not  more  than  200  feet,  and  provided  either  with  buckets 
or  large  dippers.  The  buckets  should  be  of  metal,  wood 
pulp,  or  paper.  Metal  well  painted  is  preferable.  The 
track  walker  should  examine  all  tubs  at  least  once  each 
week  and  report  their  condition  to  the  section  foreman, 
whose  business  it  is  to  keep  them  full  of  water.  Kero 
sene  barrels  sawed  in  two  make  excellent  tubs — cheap  and 
enduring. 

An  equally  important  safeguard  against  fire  is  the  cutting 
and  burning  of  all  grass  and  brush  from  the  right  of  way 
adjacent  to  the  trestle,  and  the  removal  and  burning  of  all 
rubbish  which  could  afford  any  lodgment  for  sparks.  The 
grass  and  brush  should  be  cut  early  in  the  season,  when  the 
stubble  is  too  green  to  burn. 

It  is  the  contractor's  business  to  protect  the  trestle  against 
fire  during  construction  by  the  removal  and  burning  of  all 
brush  and  rubbish  which  could  in  any  way  threaten  its 
safety.  A  clause  to  this  effect  should  have  a  place  in  every 
contract. 


RAILROAD    STRUCTURES.  1211 

FIELD    ENGINEERING    AND    ERECTING. 

1779.  Locating  Bents. — The  number  of  bents  com- 
posing the  trestle  and  the  number  of  the  station  at  the 
beginning  and  end  of  the  same  are  determined  from  an  in- 
spection of  the  profile.  The  center  line  of  the  trestle  is  then 
run  in,  a  plug  being  driven  on  the  center  line  locating  each 
bent.  It  is  customary  to  place  these  center  plugs  1  foot  in 
advance  of  the  bent  centers  so  that  they  will  not  be  dis- 
turbed while  placing  the  bents  in  position.  The  center 
plugs  being  driven,  the  transit  is  set  up  at  each  plug  and 
stakes  set  at  right  angles  to  the  center  line,  giving  the  direc- 
tion of  the  sill.  These  stakes  are,  like  the  center  plug, 
1  foot  in  advance  of  the  required  center  line  of  the  sill.  In 
case  the  trestle  is  built  on  a  curve,  the  bents  should  stand 
on  radial  lines. 

It  is  of  the  first  importance  that  the  levels  be  correct, 
and  to  facilitate  the  checking  of  them,  a  bench  mark  with 
an  elevation  of  about  the  grade  of  the  rail  should  be  estab- 
lished at  the  end  of  the  trestle,  and  another  near  the  lowest 
point  of  the  line  over  which  the  trestle  passes.  At  each 
center  plug  a  strong  stake  should  be  driven,  with  the  top  of 
the  stake  at  the  level  of  the  top  of  the  foundation  for  that 
bent.  One  grade  stake  at  each  bent  is  sufficient,  as  the  work- 
men can  transfer  that  elevation  to  other  points,  if  necessary, 
with  an  ordinary  carpenter's  or  mason's  level. 

1780.  Erecting. — Trestle  bents  of  moderate  height 
are  framed,  lying  flat  on  the  ground,  with  the  sills  so  placed 
that  when  the  bent  is  raised  it  will  occupy  its  proper  posi- 
tion. The  raising  is  effected  by  means  of  blocks  and  a  fall, 
the  power  being  ordinarily  applied  by  either  horses  or  a 
gang  of  men.  The  end  bent  is  first  raised  and  braced  in 
position,  and  the  tackle  for  raising  the  next  bent  attached 
to  it.  Stay  ropes  should  be  attached  to  a  bent  before  it  is 
raised,  to  steady  it  and  to  prevent  it  from  being  pulled  over 
after  it  has  reached  an  upright  position.  As  soon  as  a  bent 
is  raised,  it  should  at  once  be  fastened  in  position  by  means 
of    stay   lath    nailed    to    it    and    the    bent    immediately 


1212  RAILROAD   STRUCTURES. 

preceding.  The  sway-bracing  should  be  fastened  immedi- 
ately, and  when  no  longitudinal  bracing  is  to  be  added,  the 
stringers  should  be  put  in  place  and  fastened  before  raising 
another  bent. 

High  trestles,  composed  of  several  sections  placed  one 
above  the  other,  and  separated  by  purlins  (see  Fig.  627), 
are  usually  erected  as  follows:  The  bottom  deck  having  been 
raised,  the  purlins  are  placed  upon  it,  and  a  temporary  floor 
laid  on  the  purlins,  upon  which  the  bent  forming  the  next 
section  is  placed  and  raised  precisely  as  though  it  lay  on 
the  ground. 

Special  designs  require  special  methods,  but  the  plan 
generally  adopted  is  that  given  above.  A  tack  or  nail  is 
driven  in  each  cap  on  the  center  line  for  the  accurate  pla- 
cing of  the  stringers.  After  the  ties  and  guard-rails  are  in 
place  and  fastened,  tacks  are  driven  in  ties  at  intervals  of 
about  50  feet,  to  guide  the  track  layers. 

1781.  Preservation  of  Joints.  —  At  every  point 
where  two  pieces  of  timber  come  in  contact,  they  should  be 
painted  with  some  preservative  material.  As  trestle  timbers 
are  usually  rough,  a  considerable  quantity  of  material  is 
necessary,  if  all  joints  are  to  be  properly  treated  ;  white  lead, 
though  effective,  is  too  expensive.  Hot  coal  tar  is  a  cheap 
and  effective  wood  antiseptic,  and  available  everywhere. 
Creosote  oil  is  also  much  used,  and  when  the  finances  of  the 
company  admit  of  it,  a  trestle  built  of  timber  which  has 
been  thoroughly  treated  with  creosote  oil  under  pressure  is 
undoubted  economy. 

1782.  Trestle  Specifications. — There  is  no  class  of 
structures  of  the  importance  of  wooden  trestles  upon  which 
there  has  been  so  gross  neglect  in  the  matter  of  specifica- 
tions. Many  important  contracts  contain  but  a  few  lines, 
while  others  of  equal  importance  carry  specifications  purely 
general  in  character,  in  which  many  points  of  the  first  im- 
portance are  entirely  neglected.  The  following  specifica- 
tions are  general,  but  are  sufficiently  detailed  to  guide  the 
student  in  making  an  application   to  a  particular  structure: 


RAILROAD    STRUCTURES.  1213 

STANDARD  SPECIFICATIONS  FOR    \VOODEN 
TRESTLES. 


CLEARING. 

Before  commencing  work  on  any  structure,  the  ground 
must  be  entirely  cleared  of  logs,  stumps,  trees,  and  brush  of 
every  description.  All  combustible  material  must  be  piled 
at  convenient  places  and  completely  burned.  Trees  outside 
the  right  of  way  which,  by  falling,  may  endanger  the  tres- 
tle, must  be  felled  by  the  contractor,  it  being  understood 
that  permission  to  fell  such  trees  shall  be  obtained  by  the 
railroad  company  from  the  land  owner.  Such  portions  of 
the  right  of  way  as  shall  be  deemed  necessary  by  the 
engineer  shall  be  grubbed. 


DRAWINGS. 

The  drawings  are  to  the  scale  indicated  and  marked;  but 
in  all  cases  the  figures  are  to  be  taken,  and  in  case  of  omis- 
sion the  engineer  in  charge  is  to  be  referred  to  for  dimen- 
sions. Under  no  circumstances  are  the  drawings  to  be 
scaled  either  by  the  contractor  or  by  any  of  his  men.  The 
engineer  will  be  required  to  mark  the  dimensions  upon  the 
contractor's  blue-print  and  to  keep  a  record  of  the  same  in 
his  office. 

DIMENSIONS. 

All  posts,  braces,  clamps,  stringers,  packing-blocks,  ties, 
guard-timbers,  sills,  and  all  timber  generally,  will  be  of  the 
exact  dimensions  given  and  figured  upon  the  plan.  Varia- 
tions from  these  will  be  allowed  only  upon  the  written 
consent  of  the  engineer  in  charge. 


TIMBER. 

All  timber  shall  be  of  good  quality  and  of  such  kinds  as 
the  engineer  shall  direct,  and  be  free  from  wind-shakes, 
black,  loose,  or  unsound  knots,  worm  holes,  and  all  descrip- 
tions of  decay.     It  must  be  sawed  true  and  out  of  wind,  and 


1214  RAILROAD   STRUCTURES. 

full  size.  Under  no  circumstances  will  any  timber  cut  from 
dead  logs  be  allowed  to  be  placed  in  any  part  of  the  struc- 
ture; it  must  in  every  case  be  cut  from  living  trees. 


PILES. 

Piles  shall  be  cut  from  live,  thrifty  timber.  They  will 
be  either  round  or  square, as  may  be  required  by  the  engineer. 
Roimd  piles  must  be  straight,  be  stripped  of  all  bark,  and  be 
well  trimmed.  They  must  be  at  least  twelve  (12)  inches  in 
diameter  at  the  cut-off,  when  cut  to  grade  to  receive  the 
cap.  The  smaller  end  must  be  at  least  eight  (8)  inches  in 
diameter. 

Square  piles  must  be  hewn  (or  sawed)  twelve  (12)  inches 
square.  They  must  have  at  least  nine  (9)  inches  of  heart 
wood  on  each  face  from  the  head  of  the  pile  after  being  cut 
off  to  grade,  to  five  (5)  feet  below  the  surface  of  the  ground 
into  which  the  pile  is  driven. 

All  piles  must  be  properly  pointed.  They  shall,  if  re- 
quired, be  shod  with  shoes  of  cast  or  wrought  iron,  made 
according  to  plans  furnished  by  the  engineer.  In  driving 
they  shall  be  banded  with  wrought-iron  rings  of  suitable 
weight  to  prevent  splitting.  The  actual  cost,  delivered  on 
the  ground,  of  the  necessary  shoes  and  rings  will  be  allowed  to 
the  contractor.  Piles  must  be  driven  to  hard  bottom  or 
until  they  do  not  sink  more  than  five  (5)  inches  under  the  last 
five  (5)  blows  from  a  hammer  of  at  least  two  thousand  (2,000) 
pounds  weight,  falling  free  twenty-five  (25)  feet.  All  piles 
injured  in  driving,  or  driven  out  of  place,  shall  be  either 
withdrawn  or  cut  off,  as  the  engineer  may  elect,  and  others 
driven  in  their  stead.  The  piles  thus  replaced  will  not  be 
paid  for.  All  piles  under  track  stringers  must  be  accurately 
spaced  and  driven  vertically,  and  in  each  bent  the  batter 
piles  will  be  driven  at  the  angle  shown. 

Piles  shall  be  measured  by  the  lineal  foot  after  they  are 
driven  and  cut  off,  and  the  price  per  lineal  foot  shall  be 
understood  to  cover  the  cost  of  transportation,  removing 
the  bark,  driving,  cutting  off,  and  all  labor  and  materials 
required  in  the  performance  of  the  work,  but  that  portion  of 


RAILROAD    STRUCTURES.  1215 

each  pile  cut  off  shall  be  estimated  and  paid  for  by  the  lineal 
foot  as  "piles  cut  off." 

The  contractor  must  give  all  facilities  in  his  power  to  aid 
the  pile  recorder  in  his  duties. 

Parts  of  pile  heads  projecting  beyond  the  cap  must  be 
adzed  off  at  an  angle  of  45°. 


FRAMING. 

All  framing  must  be  done  to  a  close  fit  and  in  a  thorough 
and  workmanlike  manner.  No  blocking  or  shimming  of  any 
kind  will  be  allowed  in  making  joints,  nor  will  open  joints 
be  accepted. 

All  joints,  ends  of  posts,  piles,  etc.,  and  all  surfaces  of 
wood  on  wood  shall  be  thoroughly  painted  with 
*hot    creosote    oil    and    covered    with    a    coat     of     thick 
asphaltum; 
hot  asphaltum; 
hot  common  tar; 

a  good,  thick  coat  of  white  lead  ground  and  mixed  with 
pure  linseed  oil. 
All  bolt  and  other  holes  bored  in  any  part  of  the  work 
must  be  thoroughly  saturated  with 
*hot  creosote  oil; 
hot  asphaltum; 
hot  tar; 
coal  tar; 

white  lead  mixed  with  pure  linseed  oil; 
linseed  oil. 

And  all  bolts  and  drift  bolts  before  being  put  in  place 
must  be 

♦warmed  and  coated  with  hot  creosote  oil; 
warmed  and  coated  with  hot  asphaltum ; 
warmed  and  coated  with  hot  tar; 
warmed  and  coated  with  hot  coal  tar ; 
coated  with  coal  tar; 
coa'ted  with  white  lead  and  linseed  oil. 


Optional  methods  of  treatment. 


121G  RAILROAD    STRUCTURES. 

All  bolt  holes  for  bolts  three-quarters  (|)  of  an  inch  in 
diameter  or  over  must  be  bored  with  an  auger  one-eighth 
(^)  of  an  inch  smaller  in  diameter  than  the  holt,  in  order  to 
secure  a  perfectly  tight  fit  of  the  bolt  in  the  hole.  For  bolts 
five-eighths  (|)  of  an  inch  in  diameter,  or  smaller,  the  auger 
must  be  one-sixteenth  {j\)  of  an  inch  smaller,  for  the  same 
reason.  

TRESTLES  ON  CURVES. 

Trestles  built  on  curves  will  have  the  outer  rail  elevated 
according  to  plans  furnished  from  the  Chief  Engineer's 
office,  a  copy  of  which  will  be  delivered  to  the  contractor. 


CREOSOTED  TRESTLES. 

All  piles  used  in  creosoted  trestles  must  be  completely 
stripped  of  bark,  and  be  pointed  before  treatment.  None 
of  the  sap  wood  may  be  hewn  from  the  piles.  No  notching 
or  cutting  of  the  piles  will  be  allowed  after  treatment,  ex- 
cept the  sawing  off  of  the  head  of  the  pile  to  the  proper 
level  for  the  reception  of  the  cap,  and  the  beveling  of  such 
part  of  the  head  as  shall  project  from  under  the  cap. 

The  heads  of  all  creosoted  piles,  after  the  necessary  cut- 
ting and  trimming  has  been  done  for  the  reception  of  the 
cap,  must  be  saturated  with  hot  creosote  oil,  and  then  cov- 
ered with  hot  asphaltum  before  putting  the  cap  in  place. 

Timber  for  creosoted  trestles  must  be  cut  and  framed  to 
the  proper  dimensions  before  treatment.  No  cutting  or 
trimming  of  any  kind  will  be  allowed  after  treatment, 
except  the  boring  of  the  necessary  bolt  holes. 

Hot  creosote  oil  must  be  poured  into  the  bolt  holes  before 
the  insertion  of  the  bolts,  in  such  a  manner  that  the  entire 
surface  of  the  holes  shall  receive  a  coating  of  creosote  oil. 


TREATMENT  OF  CREOSOTED  PILES  AND  TIMBER. 

All  creosoted  timber  and  piles  shall  be. prepared  in 
accordance  with  the  following  process:  The  timber  and 
piles,  after  having   been  cut  and  trimmed  to   the   proper 


RAILROAD    STRUCTURES.  1217 

length,  size,  and  shape,  shall  be  submitted  to  a  contact 
steaming  inside  the  injection  cylinders,  which  shall  last 
from  two  to  three  hours,  according  to  the  size  of  the  tim- 
ber; then,  to  a  heat  not  to  exceed  230°  F.,  in  a  vacuum  of 
twenty-four  (24)  inches  of  mercury,  for  a  period  long  enough 
to  thoroughly  dry  the  wood.  The  creosote  oil,  heated  to  a 
temperature  of  about  175°,  shall  then  be  let  into  the  injec- 
tion cylinder  and  forced  into  the  wood  under  a  pressure  of 
150  pounds  per  square  inch,  until  not  less  than  15  pounds  of 
oil  to  the  cubic  foot  has  been  absorbed.  The  oil  must  con- 
tain at  least  10  per  cent,  of  carbolic  and  cresylic  acids,  and 
have  at  least  12  per  cent,  of  naphthalene. 


IRON. 

Wrought  Iron. — All  wrought  iron  must  be  of  the  best 
quality  of  American  refined  iron,  tough,  ductile,  uniform  in 
quality,  and  must  have  an  elastic  limit  of  not  less  than 
twenty-six  thousand  (26,000)  pounds  per  square  inch. 

All  bolts  must  be  perfect  in  every  respect,  and  have  nuts 
and  thread  of  the  full  standard  size  due  their  diameters. 
The  thickness  of  the  nut  shall  not  be  less  than  the  diameter 
of  the  bolt,  and  the  side  of  its  square  not  less  than  twice 
the  diameter  of  the  bolt. 

The  heads  of  all  bolts  shall  be  square ;  round  button ; 
countersunk; 

When  square  the  thickness  shall  not  be  less  than  the  diam- 
eter of  the  bolt,  and  the  side  of  its  square  not  less 
than  twice  the  diameter  of  the  bolt ; 
When  round  button  the  thickness  at  center  shall  not  be  less 
than  three-quarters  of  the  diameter  of  the  bolt,  and 
the  extreme  diameter  not  less  than  two  and  one-half 
times  the  diameter  of  the  bolt; 
When  countersunk  the  extreme  diameter  of  head  shall  not 
be    less    than    twice    the    diameter   of    the   bolt,   and 
countersunk  on  the  under  side  so  as  to  fit  into  a  cup 
washer. 
Cast  Iron. — All  castings  must  be  of  good,  tough  metal, 
of  a  quality  capable  of  bearing  a  weight  of  five  hundred  and 


1218  RAILROAD    STRUCTURES. 

fifty  (550)  pounds,  suspended  at  the  center  of  a  bar  one  (1) 
inch  square,  and  four  and  one-half  (4^)  feet  between  sup- 
ports. They  must  be  smooth,  well  shaped,  free  from  air 
holes,  cracks,  cinders,  and  other  imperfections. 

All   iron   before   leaving   the   shop   must  be  thoroughly 
soaked  in  boiled  linseed  oil. 


INSPECTION    AND   ACCEPTANCE. 

All  materials  will  be  subject  to  the  inspection  and  accept- 
ance of  the  engineer  before  being  used.  The  contractor 
must  give  all  proper  facilities  for  making  such  inspection 
thorough. 

Any  omission  by  the  engineer  to  disapprove  the  work  at 
the  time  of  a  monthly  or  any  other  estimate  being  made, 
shall  not  be  construed  as  an  acceptance  of  any  defective 
work.  

PROTECTION   AGAINST   FIRE. 

The  contractor  must,  each  evening,  before  quitting  work, 
remove  all  shavings,  borings,  and  scraps  of  wood  from  the 
deck  of  the  trestle  and  from  proximity  to  the  bents,  and 
upon  the  completion  of  the  work  must  take  down  and  re- 
move to  a  safe  distance  all  staging  used  in  the  erection  of 
the  work,  and  remove  and  burn  all  fragments  of  timber, 
shavings,  etc. 

ROADS  AND   HIGHWAYS. 

Commodious  passing  places  for  all  public  and  private 
roads  shall  be  maintained  in  good  condition  by  the  con- 
tractor, and  he  shall  open  and  maintain  thereafter  a  good 
and  safe  road  for  passage  on  horseback  along  the  whole 
length  of  his  work. 

RUNNING   OP  TRAINS. 

The  contractor  shall  so  conduct  all  his  operations  as  not 
to  impede  the  running  of  trains  or  the  operation  of  the 
road.     He  will  be  responsible  to  the  railroad  company  for 


RAILROAD    STRUCTURES.  1219 

all  injuries  to  rolling  stock  or  damages  from  wrecks  caused 
by  his  negligence.  The  cost  of  such  damage  will  be  re- 
tained from  his  monthly  and  final  estimates. 


RISKS. 

The  contractor  shall  assume  all  risks  from  floods,  storms, 
and  casualties  of  every  description,  except  those  caused  by 
the  railroad  company,  until  the  final  estimate  of  the  work. 


LABOR   AND   MATERIAL. 

The  contractor  must  furnish  all  labor  and  material  inci- 
dental to  or  in  any  way  connected  with  the  manufacture, 
transportation,  erection,  and  maintenance  of  the  structure 
until  its  final  acceptance. 

Disorderly,  quarrelsome,  or  incompetent  men  in  the  employ 
of  the  contractor,  or  those  who  persist  in  doing  bad  work  in 
disregard  of  these  specifications,  must  be  discharged  by  the 
contractor  when  requested  to  do  so  by  the  engineer. 

Whenever  the  chief  engineer  may  deem  it  advisable,  he 
may  name  the  rates  and  prices  to  be  paid  by  the  contractors, 
for  such  time  as  he  may  designate,  to  the  several  classes  of 
laborers  and  mechanics  in  their  employ,  and  for  the  hire  of 
horses,  mules,  teams,  etc.,  and  these  shall  not  be  exceeded; 
and  having  given  due  notice  to  the  contractors  of  his  action 
in  regard  to  these  matters,  they  shall  be  boirwfl  to  "obey  his 
orders  in  relation  thereto.  The  chief  engineer  shall  not, 
however,  name  a  rate  or  price  for  any  class  of  labor,  etc., 
higher  than  the  maximum  rates  being  paid  by  the  contractor 
paying  the  highest  for  that  class. 


INTOXICATING   LIQUORS. 

Contractors  will  not  themselves,  nor  by  their  agents,  give 
or  sell  any  intoxicating  liquors  to  their  workmen  or  to  any 
persons  at  or  near  the  line  of  the  railway,  nor  allow  any 
to  be  brought  on  the  works  by  the  laborers  or  any  other 
person,  and  will  do  all  in  their  power  to  prevent  their  use  in 
the  vicinity  of  the  work   by  persons   in    their  employ.     A 


1220  RAILROAD    STRUCTURES. 

continued  disregard  for  this  clause  will,  if  deemed  necessary 
by  the  engineer,  be  considered  as  a  good  and  sufficient  reason 
for  declaring  the  contract  forfeited. 


DAMAGES   AND  TRESPASS. 

Contractors  shall  be  liable  for  all  damages  to  landholders, 
arising  from  loss  of  or  injury  to  crops  or  cattle,  sustained 
by  any  cause  or  thing  connected  with  the  works  or  through 
any  of  their  agents  or  workmen.  They  will  not  allow  any 
person  in  their  employ  to  trespass  upon  the  premises  of  per- 
sons in  the  vicinity  of  the  works,  and  will  forthwith,  at  the 
request  of  the  engineer,  discharge  from  their  employ  any 
person  that  may  be  guilty  of  committing  damage  in  this 
respect.  They  will  also  maintain  any  fences  that  may  be 
necessary  for  the  proper  protection  of  any  property  or 
crops. 

REMOVAL  OF   DEFECTIVE  ^VORK. 

The  contractor  will  remove  at  his  own  expense  any  ma- 
terial disapproved  by  the  engineer,  and  will  remove  and 
rebuild,  without  extra  charge,  and  within  such  time  as  may 
be  fixed  by  the  engineer,  any  work  appearing  to  the  engin- 
eer, during  the  progress  of  the  work  or  after  the  comple- 
tion, to  be  unsound,  or  improperly  executed,  notwithstand- 
ing that  any  certificate  may  have  been  issued  as  due  for  the 
execution  of  the  same.  The  engineer  shall,  however,  give 
notice  of  defective  work  to  the  contractor  as  soon  as  he 
shall  have  become  cognizant  of  the  same.  On  default  of 
the  contractor  to  replace  the  work  as  directed  by  the  engin- 
eer, such  work  may  be  done  by  the  railroad  company  at  the 
contractor's  expense. 

DELAYS. 

No  charge  shall  be  made  by  the  contractor  for  hin- 
drances and  delay,  from  any  cause,  in  the  progress  of  the 
work;  but  it  may  entitle  him  to  an  extension  of  the  time 
allowed  for  completing  the  work,  sufficient  to  compensate 


RAILROAD    STRUCTURES.  1221 

for  the  detention,  to  be  determined  by  the  engineer,  pro- 
vided he  shall  give  the  engineer  in  charge  immediate  notice, 
in  writing,  of  the  detention. 


EXTRA   WORK. 

No  claim  shall  be  allowed  for  extra  work,  unless  done  in 
pursuance  of  a  written  order  from  the  engineer,  and  unless 
the  claim  is  made  at  the  first  estimate  after  the  work  is  ex- 
ecuted. The  chief  engineer  may,  at  his  discretion,  allow 
any  claim,  or  such  part  of  it  as  he  may  deem  just  and 
equitable. 

Unless  a  price  is  specified  in  the  contract  for  the  class  of 
work  performed,  extra  work  will  be  paid  for  at  the  actual 
cost  of  the  material  remaining  in  the  structure  after  its 
completion  and  the  cost  of  the  labor  for  executing  the  work 
plus  fifteen  (15)  per  cent,  of  the  total  cost.  This  fifteen 
(15)  per  cent,  will  be  understood  to  include  the  use  and  cost 
of  all  tools  and  temporary  structures,  staging,  etc.,  and  the 
contractor's  profit,  and  no  extra  allowance  over  and  above 
this  will  be  made.  

INFORMATIOIV   AND   FORCE   ACCOUNTS. 

The  contractor  will  aid  the  engineer  in  every  way  possible 
in  obtaining  information,  and  freely  furnish  any  which  he 
may  possess,  by  access  to  his  books  and  accounts,  in  regard 
to  the  cost  of  work,  labor,  time,  material,  force  account, 
and  such  other  items  as  the  engineer  may  require  for  the 
proper  execution  of  his  work,  and  shall  make  such  reports  to 
him  from  time  to  time  as  he  may  deem  necessary  and 
expedient.  

PROSECUTION   OF   THE    WORK. 

The  contractor  shall  commence  his  work  at  such  points  as 
the  engineer  may  direct,  and  shall  conform  to  his  directions 
as  to  the  order  of  time  in  which  the  different  parts  of  the 
work  shall  be  done,  as  well  as  the  force  required  to  complete 
the  work  at  the  time  specified  in  the  contract.  In  case  the 
contractor  shall  refuse  or  neglect  to  obey  the  orders  of  the 
engineer  in  the  above  respects,  then  the  engineer  shall  have 


1222  RAILROAD   STRUCTURES. 

the  power  to  either  declare  the  contract  null  and  void  and 
relet  the  work,  or  to  hire  such  force  and  buy  such  tools  at 
the  contractor's  expense  as  may  be  necessary  for  the  proper 
conduct  of  the  work,  as  may,  in  his  judgment  be  for  the  best 
interests  of  the  railroad  company. 


CHANGES. 

At  any  time  during  the  execution  or  before  the  commence- 
ment of  the  work,  the  engineer  shall  be  at  liberty  to  make 
such  changes  as  he  may  deem  necessary,  whether  the  quan- 
tities are  increased  or  diminished  by  such  changes,  and  the 
contractor  shall  not  be  entitled  to  any  claim  on  account  of 
such  changes  beyond  the  actual  amount  of  work  done  ac- 
cording to  these  specifications  at  the  prices  stipulated  in  the 
contract,  unless  such  work  is  made  more  expensive  to  him, 
when  such  rates  as  may  be  deemed  just  and  equitable  by  the 
chief  engineer  will  be  allowed  him ;  if,  on  the  other  hand, 
the  work  is  made  less  expensive,  a  corresponding  deduction 
may  be  made.  

QUANTITIES. 

It  is  distinctly  understood  that  the  quantities  of  work  es- 
timated are  approximate,  and  the  railroad  company  reserves 
the  right  of  having  built  only  such  kinds  and  quantities,  and 
according  to  such  plans,  as  the  nature  or  economy  of  the 
work  may,  in  the.  opinion  of  the  engineer,  require. 


ENGINEER. 

The  term  engineer  will  be  understood  to  mean  the  chief 
engineer,  or  any  of  his  authorized  assistants  or  inspectors, 
and  all  directions  given  by  them,  under  his  authority,  shall 
be  fully  and  implicitly  followed,  carried  out,  and  obeyed  by 
the  contractor  and  his  agents  and  employes. 


PRICE   ANI>   PAYMENT. 

The  prices  bid  will  include  the  furnishing  of  materials, 
tools,  scaffolding,  watching,  and  all  other  items  of  expense 
in  any  way  connected  with  the  execution  and  maintenance 


RAILROAD    STRUCTURES.  1223 

of  the  work  until  it  is  finally  accepted  and  received  as  com- 
pleted. The  contractor  will  be  paid  only  for  the  piles,  tim- 
ber, and  iron  left  in  the  structure  after  completion.  No 
wastage  in  any  kind  of  material  will  be  paid  for  except  in  the 
case  of  piles,  when  the  "  piles  cut  off,"  which  can  not  be  used 
on  any  other  part  of  the  contractor's  work,  will  be  paid  for 
at  the  rate  agreed  upon.  After  the  material  cut  off  is 
paid  for,  it  is  to  be  considered  the  property  of  the  railroad 
company,  and  is  to  be  neither  removed  nor  used  by  the  con- 
tractor without  the  consent  of  the  engineer,  and  then  only 
upon  the  repayment  of  the  price  which  has  been  paid 
for  it. 

The  piles  and  "piles  cut  oft"  will  be  paid  for  by  the  lineal 
foot,  the  former  driven  in  place. 

The  timber  and  lumber  remaining  in  and  necessary  to  the 
completed  structure  will  be  paid  for  by  the  thousand  feet, 
board  measure. 

The  iron  will  be  paid  for  by  the  pound,  and  only  that 
remaining  in  the  structure  after  its  completion. 

The  masonry  for  foundations  will  be  paid  for  by  the  cubic 
yard. 

The  excavations  for  foundations  will  be  paid  for  by  the 
cubic  yard. 

The  retained  percentage  will  not  be  paid  on  the  cost  of 
any  single  structure  until  the  final  estimate  is  due  on  the 
entire  work  embraced  in  the  contract. 

When  the  trestling  and  grading  are  let  under  one  con- 
tract, or  when  a  general  contract,  as  by  the  miU\  includes 
a  considerable  portion  or  all  of  a  line,  many  of  the 
preceding  clauses  will  be  omitted  in  the  section  of  the  con- 
tract pertaining  to  trestles,  as  they  are  general  require- 
ments applicable  to  all  classes  of  work  embraced  by  the 
contract.  Special  conditions  obtaining  in  a  particular 
section  of  the  country  may  also  require  modifications  of 
some  of  the  given  clauses.  The  specifications  given  are 
general  and  are  intended  to  meet  all  certain  requirements 
and  secure  justice  to  both  the  contractor  and  the  railroad 
company. 


1224 


RAILROAD   STRUCTURES. 


BILLS  OF  MATERIAL,  RECORDS,  AND 
MAINTENANCE. 
1783.  Proper  Forms. — Proper  forms  of  bills  of  ma- 
terial are  of  great  importance  to  both  contractor  and  en- 
gineer: to  the  former  in  ordering  and  placing  material,  and 
to  the  latter  in  checking,  estimating,  and  keeping  records  of 
the  same.  Few  young  engineers  have  any  knowledge  of 
such  forms,  and  many  engineers  of  experience  have  been  con- 
tent with  slovenly  cut-and-try  methods.  The  following  is 
a  proper  form  of  bill  of  material: 


TRESTLE    NO.    2. 


DIVISION    NO.   4. 


RESIDENCY    NO.   3. 


BILL   OF   IRON. 


No.  of 
Pieces. 

Name. 

Use. 

Size. 

Weight. 

WROUGHT    IRON. 

24 

Drift-bolts 

Stringers  to  bank  sills 

i"  sq.  X  24' 

26 

Drift-bolts 

Stringers  to  caps.  .  . . 

f ' sq. X  24' 

6 

Drift-bolts 

Sills  to  mud-sills.  .  .  . 

r  sq. X  20' 

102 

Boat  spikes 

Ties  to  stringers  .... 

Yxir 

150 

Boat  spikes 

Guard-rails  to  ties.  .  . 

VxW 

26 

Bolts 

Guard-rails    to  jack- 
stringers  

rx31i' 

12 

Bolts 

Caps  to  posts 

rx22' 

16 

Bolts 

Sway-bracing 

|'X20' 

32 

Bolts 

To 

Packing  for  stringers 
tal 

f'x22' 

CAST    IRON. 

172 

Washers. .  . 

Under  heads  and  nuts 

Separators 

of  bolts 

rx3' 

2''X3' 

32 

Between  stringers. .  . 

To 

tal 

All  bills  of  material  should  be  copied  in  a  letter  book.  In 
making  out  bills  of  material,  the  contractor  should  be  al- 
lowed the  full  length  of   each   stick,  including  the  tenon, 


RAILROAD   STRUCTURES. 


1225 


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122G  RAILROAD   STRUCTURES. 

and  where  the  tenon  is  cut  on  a  skew,  as  in  batter  posts, 
etc.,  the  full  size  for  the  extreme  length  of  stick  should  be 
reckoned. 

1  784.  The  number  of  feet  B.  M.  (board  measure)  in  a 
stick  of  timber  or  in  lumber  1  inch  or  over  in  thickness  is 
found  by  the  following  rule: 

Mtiltiply  together  the  breadth  and  thickness  in  inehes  and 
the  length  of  the  stick  in  feet,  and  divide  the  product  by  12. 
The  quotient  will  be  the  number  of  feet  required. 

If  we  denote  the  breadth  by  b,  the  thickness  by  /,  and  the 
length  by  Z,  we  may  put  the  question  in  algebraic  form  as 

f°"°*^ ■■        Feet  B.  M.  =  *-H^.  ( 1 26.) 

When  lumber  is  less  than  1  inch  in  thickness,  it  is  always 
reckoned  as  though  it  were  a  full  inch  thick. 

A  table  like  the  following,  containing  the  number  of  feet 
B.  M.  in  each  piece  entering  into  the  standard  trestle  will 
greatly  facilitate  the  making  out  of  bills  of  material: 

General.  — Each  trestle  will  require: 

8  Bank  sills,  12'  X  12'  X  12'  0' 1,152  ft.,  B.  M. 

4  Dump  boards,  4'  X  8'  X  11'  4' 121  ft.,  B.  M. 

Stringer  pieces,  8'  X  16'  X  25'  0' contain  each    267  ft.,  B.  M. 

Ties,  6'  X  8'  X  12'  0'  contain  each 48  ft. ,  B.  M. 

Guard-rails,  6'  X  8'  X  20'  0'  contain  each 80  ft.,  B.  M. 

1785.  Inspection. — After  the  road  is  completed  and 
turned  over  to  the  operating  and  maintenance  depart- 
ments, the  trestles,  as  well  as  all  other  structures  forming  a 
part  of  the  roadway,  should  be  regularly  and  thoroughly  in- 
spected. At  least  once  every  year,  at  a  favorable  season, 
the  work  of  inspection  should  be  performed  by  the  en- 
gineer in  charge  of  the  maintenance-of-way  department.  The 
inspection  should  be  thorough  in  every  detail,  and  where  the 
traffic  is  heavy,  this  inspection  should  be  made  twice  a  year. 

Once  each  month  all  structures  should  receive  a  careful 
examination  by  a  competent  inspector.  Not  only  the  deck 
timbers,  but  all  timbers  entering  into  the  structure,  should 
be  examined,  and  every  necessary  help  should  be  afforded 


RAILROAD    STRUCTURES. 


1227 


the  inspector  to  facilitate  his  work.  He  should  make  out  a 
complete  report  on  proper  blanks  of  the  condition  of  each 
structure,  forwarding  them  to  either  the  division  engineer 
or  division  superintendent,  who,  having  examined  and  ap- 
proved the  reports,  forwards  them  to  the  engineer  of  main- 
tenance of  way. 

A  further  inspection  should  be  made  by  the  track  walker^ 
and  that  as  often  as  he  crosses  the  bridge  or  trestle,  though 
it  be  several  times  a  day.  Of  course,  the  inspection  of  the 
latter  will  consist  only  of  a  general  oversight,  but  sufficient 
to  detect  at  once  any  exterior  defect  or  lack.  The  track 
walker  will  be  provided  with  blanks  for  making  out  reports. 
The  following  form  is  suitable  for  his  report: 

BLACK  RIVER  VALLEY   RAILROAD. 


TRACK  l^VALKEH'S   DAILY   REPORT   0!V   THE  CONDITION 
OF  BRIDGES   AND   TRESTLES. 


Number  of 

Time. 

Condition. 

Bridge. 

A.  M. 

P.  M. 

A.  M. 

p.  M. 

M.  P.  123  A 

7:45 

5:45 

X 

X 

M.  P.  123  B 

8:10- 

5:20 

X 

X 

M.  P.  124  A 

8:30 

4:50 

X 

X 

M.  P.  124  B 

9:00 

4:20 

X 

X 

M.  P.  124  C 

9:50 

3:50 

X 

X 

M.  P.  125  A 

10:30 

3:30 

X 

X 

M.  P.  125  B 

10:50 

3:00 

X 

X 

M.  P.  126  A 

11:20 

2:30 

X 

X 

M.  P.  126  B 

11:45 

1:40 

X 

X 

M.  P.  126  C 

12:00 

1:10 

X 

X 

Track  Walker. 


.189. 


These  blanks  are  bound  in  pads  of  fifty  sheets  and  carry 
a  pasteboard  cover  for  protection.  When  filled  out  the  re- 
port is  folded  and  endorsed  on  the  back : 


1228  RAILROAD   STRUCTURES. 

BLACK   RIVRR    VALLEY   RAILROAD. 

Track  Walker  s  Daily  Report. 
Bridges  and  Trestles  from  *M.  P.  123  A  to  M.  P.  126  C. 
In  the  report,  X  in  the  column  headed  Condition,  means 
"all  right;"  O  means  "  injured  or  unsafe,"  by  fire,  washout, 
or  from  other  cause.  In  case  of  danger,  the  fact  must  be 
reported  by  telegraph  from  the  nearest  station  to  the  in- 
spector of  bridges,  the  division  engineer,  and  the  division 
superintendent. 

1 786.     Inspector's  Tools  and  Their   Use. — An    ax 

or  hatchet  and  small  auger  are  the  essential  part  of  an 
inspector's  outfit.  Decay  generally  commences  at  the  sur- 
face of  timber,  and  is  at  once  manifest.  On  the  other 
hand,  dry  rot,  or  powder  post,  as  it  is  vulgarly  termed,  com- 
mences beneath  the  surface,  and  it  frequently  happens  that 
a  piece  of  timber,  which  from  the  surface  appears  perfectly 
sound,  is  totally  decayed  inside,  leaving  only  a  shell  of  sound 
timber.  Where  this  form  of  decay  is  in  an  advanced  stage, 
it  may  be  detected  by  striking  a  few  blows  upon  the  surface 
of  the  timber,  which  will  give  a  hollow  sound ;  but  where  the 
shell  is  thick,  the  defect  may  be  revealed  by  boring  a  small 
hole  into  the  timber,  the  degree  of  ease  with  which  the  hole 
is  bored  determining  the  degree  of -soundness  of  the  timber. 
The  simplest,  and  an  excellent  way  as  well,  of  testing  tim- 
ber is  by  driving  a  slim  wire  nail  or  spike  into  the  wood;  the 
soundness  of  the  timber  in  this  case,  as  in  boring,  will  be 
revealed  by  the  ease  or  difficulty  in  driving  the  nail. 
Whenever  a  hole  is  bored,  it  should  be  plugged  as  soon  as  it 
has  served  its  purpose,  and  but  few  holes  should  be  bored 
in  the  same  stick. 

Piles  in  trestles  need  not  be  examined  for  decay  until  they 
have  been  several  years  in  the  ground ;  but  whenever  there 
is  any  suspicion  of  decay,  an  examination  should  be  made  at 
once.  Decay  first  attacks  the  piles  at  or  near  the  surface  of 
the  ground,  and,  in  order  to  examine  them,  the  earth  must 
be  removed  to  the  depth  of  1  foot,  or  more  if  necessary.  A 
short,  sharp-pointed  steel  bar  is  a  good  tool  for  testing  the 

*  Mile  post. 


RAILROAD    STRUCTURES. 


1229 


soundness  of  piles.  After  a  pile  has  been  examined,  the 
cavity  made  for  the  examination  should  be  refilled  and  the 
earth  well  tamped. 

In  every  case  where  a  serious  defect  is  discovered,  which 
in  any  way  threatens  the  safety  of  the  structure,  the  inspector 
should  at  once  notify,  by  telegraph  from  the  nearest  station, 
the  division  engineer  and  division  superintendent  of  the 
fact,  stating  as  briefly  and  clearly  as  possible  the  nature  and 
extent  of  the  defect  or  damage, 

1  787.  Bridge  Numbers. — On  most  roads  the  bridges 
and  trestles  are  numbered  consecutively,  beginning  at  the 
terminus  of  the  road.  A  much  better  way,  now  being 
introduced,  is  to  number  the  bridges  alphabetically,  com- 
mencing at  each  mile  post  (M.  P.).  Thus,  bridge  No.  96  A 
means  the  first  bridge  after  passing  mile  post  96,  and  at 
once  conveys  to  the  mind  a  definite  idea  of  location.  On 
the  other  hand,  bridge  No.  125,  unless  some  other  explana- 
tory reference  is  given,  is  of  small  aid  in  locating  a  bridge. 
Bridge  numbers  are  usually  painted  in  black  figures  three 
inches  in  height  on  a  white  ground. 
A  l|-inch  pine  board  of  suitable  width 
is  given  four  or  five  coats  of  white  lead, 
and  the  numbers  painted  upon  it  in 
heavy  distinct  lines.     The  boards  should 


-6^ 


J 

On 
GMurd'y 
rail 


H 


^^ 


wv/A 


Fig.  630. 


Fig.  621. 


be  of  uniform  height,  and  uniformly  placed.  The  first  right- 
hand  cap  of  a  trestle  and  the  first  right-hand  tie  of  an  open 
culvert  on  passageway  are  suitable  locations  for  bridge 
numbers.  Suitable  forms  of  bridge  numbers  are  shown  in 
Figs.  620  and  621. 


1230 


RAILROAD   STRUCTURES. 


STANDARD    TRESTLE   PLANS. 

1788.  In  this  section,  the  purpose  is  to  illustrate  by 
complete  plans  the  various  types  of  trestles  in  general  use, 
whose  efficiency  has  been  proved  by  long  service. 


STANDARD   SIIVGLE-TR ACK   PILE    TRESTLE. 

1789.     In  Fig.  622  is  given  apian  of  a  pile  trestle  suit- 
able for  heights  of  from  6  to  20  feet.     On  roads  with  only  a 

moderate  traffic, 
bents  of  three  piles 
each  may  be  safely 
used  for  heights  of 
from  0  to  10  feet, 
but  for  all  through 
lines  no  trestle  bent 
should  contain  less 
than    four    piles, 


having  at  the  cut-off   point   a   diameter  of  not   less   than 
12  inches,  inside  of  bark  measurement. 

It  is  customary  to  notch  down  the  caps  1  inch  on  the  pile 
heads.  The  main  object  for  this  notching  is  to  hold  the 
piles  in  place  while  they  are  being  drift-bolted,  in  case  they 
have  been  sprung  in  driving.  The  caps  are  drift-bolted  to 
the  piles  with  f  in.  diam.  X  24  in.  drift-bolts,  and  the  stringers 
to  the  caps  with  drift-bolts  of  the  same  dimensions.  The 
ties  are   not   fastened  to  the  stringers,  but    notched  down 


RAILROAD   STRUCTURES.  1231 

1  inch  over  the  stringers,  which  prevents  any  lateral  move- 
ment. The  guard-rails  are  so  close  to  the  rails  that  in  case 
of  derailment  the  weight  of  the  derailed  engine  or  car  will 
bear  almost  directly  upon  the  strrnger.  This  form  of  trestle 
is  simple  and  thoroughly  efficient. 

DIMENSIONS    OF    TIMBERS. 

Floor  System  : 

Guard-rails,  7  in.  x  7  in.  x  20  ft.,  notched  1  in.  over  ties. 
Ties,  7  in.  X  8  in.  X  9  ft.,  notched  1  in.  over  stringers. 
Stringers,  8  in.  X  16  in.  X  24  ft.,  sized  over  caps  to  15  in. 
Packing-blocks,  2  in.  X  16  in.  X  -t  ft.,  notched  3  in.  over 
caps. 
Bents:  Caps,   12  in.  X  12  in.  X  14  ft.,  notched  1  in.  over 
pile  heads. 
Piles,  at  least  12  in.  in  diameter  at  cut-off. 

DIMENSIONS    OF    IRON    DETAILS. 

Bolts:  -^  in.  X  15^  in.,  guard-rails  to  ties. 

f    in.  X  20^   in.,    through     stringers    at     packing- 
blocks. 

Drift-bolts,  f  in.  diam.  X  24  in.,  stringers  to  caps  and  caps 
to  piles. 


STANDARD    FRAMED    TRESTLE,    PENNSYLVANIA 
RAILROAD. 

1 790.  The  standard  single-track  framed  trestle,  as 
employed  by  the  Pennsylvania  Railroad,  is  shown  in  Fig. 
623.  Like  all  standard  structures  in  use  on  this  important 
line,  this  trestle  is  a  model  structure,  combining  great 
strength  and  simplicity  of  design.  Its  characteristic  fea- 
tures are  in  the  arrangement  of  the  posts,  by  which  the 
weight  of  the  load  is  about  equally  divided  between  the 
vertical  and  the  batter  posts,  and  in  the  longitudinal  bra- 
cing, shown  in  detail  at  A.  It  will  be  observed  that  only  in 
trestles  exceeding  a  height  of  20  feet  are  the  posts  given 
dimensions  so  large  as  12  in.  X  12  in.  in  cross-section,  and 
then  only  in  the  vertical  posts.  On  the  other  hand,  the 
stringer  dimensions  which  are  commonly  adopted  on  other 
lines  are  considerably  exceeded  in  this  trestle.     For  spans 


1232 


RAILROAD   STRUCTURES. 


of  14  feet,  two  stringer  pieces  are  required,  each  10  in.  x  IT 

r^r^ — qv — ^^^^ — c=l— r^l 


Fig.  623. 

in.,  and  for  spans  of  16  feet  three  pieces,  each  8  in.  x  17  in. 
This  places  the  excess  of  timber,  if  any,  where  it  is  most 


RAILROAD   STRUCTURES.  1233 

likely  to  be  needed.  Many  trestles  are  weak  in  the  stringers, 
especially  those  designed  for  light  traffic.  On  account  of 
traffic  interchange,  these  trestles  are  continually  required 
to  carry  loads  for  which  they  were  not  designed,  and  often 
far  beyond  the  point  of  safety.  Numerous  accidents  have 
occurred  directly  attributable  to  this  cause.  In  designing 
a  trestle,  due  regard  must  be  paid  to  this  point.  A  little 
extra  timber  in  the  stringers  will  not  add  greatly  to  the 
cost  of  the  structure,  and  will  vastly  increase  its  efficiency 
and  the  reputation  of  the  road. 

Special  attention  is  called  to  the  ties,  which  are  much 
above  the  average  in  size  of  cross-section,  though  propor- 
tionately below  the  average  in  length.  The  same  is  true 
in  the  length  of  caps,  which  in  trestles  below  20  feet  in 
height  are  only  10  feet  in  length,  and  in  those  of  greater 
height  only  12  feet  in  length,  whereas  14  feet  is  the  length 
generally  adopted.  This  is  unquestionably  saving  timber 
to  good  purpose.  It  is  a  mistake  to  space  the  guard-rail 
more  than  15  inches  from  the  track  rail,  and  12  inches  is 
amply  sufficient.  The  purpose  of  the  guard-rail  is  to  keep 
the  derailed  engine  or  car  upon  the  trestle,  and  the  less  the 
space  between  the  rail  and  the  guard-timber,  the  less  will 
be  the  danger  of  the  ties  being  broken  off  by  sudden  shock 
and  weight  brought  upon  them.  Where  a  wide  space  is  left 
between  the  rail  and  the  guard  timber,  a  jack-stringer  is 
indispensable,  but  it  would  seem  a  better  policy  to  put  the 
extra  timber  forming  the  jack-stringers  into  the  track 
stringers,  and  with  the  extra  length  of  tie  make  a  shorter 
tie  with  larger  cross-section.  Batter  posts  have  a  batter  of 
3  inches  to  the  foot.  Mortises  and  tenons  for  the  smaller 
posts  are  3  in.  x  5  in.  X  7  in.,  and  for  the  larger  posts 
3  in.  X  5  in.  X  8  in. 

DIMENSIONS   OF    TIMBERS. 

Floor  System  : 

Guard-rails,  5  in.    X  8  in.,  notched  1  in.  over  ties. 
Ties,  7  in.  X  10  in.  X  9  ft.,  notched  ^  in.  to  receive  guard- 
rails, and  ^  in.  over  stringers. 


1234  RAILROAD    STRUCTURES. 

Stringers : 


Clear  Span. 

Number  of  Pieces 
Under  Each  Rail. 

Width  of  Each 
Piece. 

Depth  of 
Stringers. 

10 

2 

8  in. 

15  in. 

12 

2 

8  in. 

16  in. 

14 

2 

10  in. 

17  in. 

16 

3 

8  in. 

17  in. 

Packing-blocks,  2  in.  x  18  in.  x  0  ft. 

Bents  under  20  ft.  :     Cap,   10  in.  X  12  in.  X  10  ft. 

Plumb  posts,  10  in.  X  12  in. 

Batter  posts,  10  in.  x  10  in. ;  batter  3  in.  to  1  ft. 

Sill,  10  in.  X  12  in. 

Bents  20  ft.  and  over  :    Cap,  12   in.  x  14  in.  X  12  ft. 

Plumb  posts,  12  in.  x  12  in. 

Batter  posts,  10  in.  x  12  in. ;  batter  3  in.  to  1  ft. 

Sill,  12  in.  X  12  in. 

Sway-bracing,  3  in.  x  10  in. 

Bracing :  Longitudinal,  8  in.  X  8  in. 

Treenails :  Locust,  1  in.  in  diameter. 

DIMENSIONS    OF     IRON    DETAILS. 

Bolts:  f  in.  X ;  guard-rails  to  ties. 

f  in.  X ;  guard-rail  joints. 

f  in.  X ;  stringer  joints;  packing-blocks. 

f  in.  X ;  sway-bracing  to  caps  and  sills; 

3  in.   wrought-iron  washers  used. 

Drift-bolts  (ragged):    1   in.  X  24  in. ;  stringers  to   caps. 

Spikes :     Boat,  f  in.  x  9  in. ;  guard-rails  to  ties. 


^  in.  X  8  in. 
Cut, X 


Wrought-iron   washers  : 


;  sway-braces  to  posts. 

longitudinal  braces  to  caps 
and  sills. 

2^  in.    square  for   J-in.  bolt. 

3     in.    round  for  f-in.   bolt. 


RAILROAD    STRUCTURES. 


1235 


STANDARD   FRAMED  TRESTLE,  CLEVELAND  AND  CANTON 

RAILROAD. 

1791.  A  style  of  trestle  which  is  aptly  called  a  com- 
pound timber  trestle,  and  growing  much  in  favor,  is 
illustrated  in  Fig. 
624.  The  character- 
istic feature  of  this 
type  is  that  the  main 
members,  such  as 
stringers,  caps,  posts, 
sills,  etc.,  are  com- 
posed of  two  or  more 
pieces  bolted  to- 
gether. The  princi- 
pal ■  advantages  of 
this  style  of  construc- 
tion are  in  the  re- 
duction of  the  cost 
of  timber  and  in  the 


facility  and  safety  with  which  repairs  can   be   made.     As 
the  parts  are  bolted  together,   a   defective   piece    may   be 


1236  RAILROAD   STRUCTURES. 

readily  replaced,  and  that  without  endangering  or  delaying 
traffic.  In  general,  a  better  quality  of  timber  may  be  had 
in  small  dimensions  than  in  large  ones,  and  at  much  less 
cost.  As  the  pieces  forming  each  member  are  separated 
from  each  other,  there  is  a  complete  circulation  of  air  through- 
out the  structure,  which  seasons  and  preserves  the  timber. 

The  amount  of  iron  in  the  structure  is  necessarily  large, 
but  if  it  is  well  dipped  in  tar  or  asphaltum  before  being 
placed  in  the  structure,  the  iron  should  outlast  two  or  three 
wooden  structures.  This  form  of  trestle  is  no  more  expen- 
sive to  build  than  a  framed  structure,  and  its  popularity  is 
ample  evidence  of  its  general  excellence. 

DIMENSIONS    OF    TIMBERS. 

Floor  System  : 

Guard-rails,  8  in.  x  8  in.,  notched  1  in.  over  ties. 
Ties,  7  in.  X  9  in.  x  8  ft.  4  in. ,  notched  1  in.  over  stringers. 
Stringers,  7  in.  x  14  in.  x  30  ft.,  notched  1  in.  over  capa 
in.  X  15  in.  x  20  in. 


i3ii 
'M  3  ii 


Brace  blocks,  ,  _  .         _  .         ^  .  . 
'  (  3  m.  x  15  m.  X  34  m. 

Bents :     Caps,  6  in.  x  12  in.  X  12  ft. 
All  posts,  6  in.  X  12  in. 
Sills,  6  in.  x  12  in. 
Sway-braces,  3  in.  x  10  in. 
Tenon  blocks,  3  in.  X  12  in.  X  3  ft. 

Longitudinal  Braces  :  Girts,  4  in.  X  10  in.  X  17  ft. 

T..  ,      (  6  in.  X  8  in. 

Diagonals,  ]  3  ._^^  g  ._^ 

DIMENSIONS    OP^    IRON     DETAILS. 

Bolts  :         f  in.  X  14  in. ;  guard-rails  to  ties. 

I  in.  X  26  in. ;  stringer  joints;  packing-bolts. 
I  in.  X  21  in. ;  sway-braces  to  posts  and  at  inter- 
section of  diagonal  longitudinal  braces. 
I  in.  X  23  in. ;  longitudinal  girts  to  plumb  posts. 
I  in.  X  19  in.  ;  Iqngitudinal  girts  to  batter  posts. 
I  in.  X  18  in. ;  packing-bolts  for  posts. 
f  in.  X  26  in. ;  interior  diagonal  braces  to  posts. 


RAILROAD   STRUCTURES. 


1237 


„j     .  j  f  in.  X  3  in. 

(  1  in.  X  S^  in. 
Separators :     2  in.  X  3|  in. 


STANDARD    FRAMED    TRESTLE,    OHIO    COXNECTING 
RAILWAY. 

1792.  In  Fig.  G25  we  have  the  standard  framed  trestle 
adopted  by  the  Ohio  Connecting  Railway.  For  heights 
under  30  feet,  the  bent  consists  of  one  deck,  but  for  heights 


Fig.  625. 
above  30  feet  two  decks  are  employed,  as  shown  in  the 
figure.  As  the  middle  posts  are  directly  under  the  rails, 
they  carry  a  large  share  of  the  load,  and  to  distribute  this 
load  the  counter  posts  a  b  and  c  d are  employed.  The  inner 
posts  are  given  a  batter  of  ^  inch  to  the  foot,  which  helps 
to  distribute  the  load.  The  sub-sills  are  inexpensive,  fairly 
enduring,  and  easily  renewed.  The  foundations  should  be 
of  masonry  if  the  trestle  is  to  be  permanent,  and  if  the- 
situation  does  not  admit  of  masonry,  piles  should  be  used. 


1238  RAILROAD    STRUCTURES. 

DIMENSIONS   OF    TIMBERS. 

Floor  System  : 

Guard-rails,  8  in.  x  8  in.  x20  ft.,  notched  1  in.  over  ties 
Ties,  7  in.  X  8  in.  X  10  ft.,  notched  1  in.  over  stringers. 
Stringers,  9  in.  x  10  in.  x  28  ft.,  notched  1  in.  over  caps. 
Bents:     Caps,  -12  in.  X  12  in.  X  14  ft. 
Posts,  12  in.  X  12  in. 
Counter  posts,  10  in.  x  12  in. 
Sills,  12  in.  X  12  in. 
Sway-braces,  3  in.  X  10  in. 
Longitudinal  Braces :     Girts,  8  in.  X  12  in. 

DIMENSIONS   OF   IRON    DETAILS. 

Bolts  :     f  in.  X  IG^  in. ;  guard-rails  to  ties. 

-  .   '      ,-,;.'[■  sway-braces  to  caps  and  sills, 
f  in.  X  17^  in.  )         -^  ^ 

f  in.  X  22:J-  in.  ;  purlins  to  posts. 

f  in.  X  23    in. ;  stringers  to  caps. 

"Washers  :     f  in.  X  3  in. 


STANDARD    DOUBLE-TRACK    PILE    TRESTLE,    BOSTON 
AND     ALBANY     RAILROAD. 

1793.  A  double-traclc  trestle  is  nothing  rnor*  than 
two  single-track  trestles  so  combined  as  to  form  one  struc- 
ture. In  Fig.  G2(!,  we  have  the  standard  double-track  pile 
trestle  as  adopted  by  the  Boston  and  Albany  Railroad. 
The  two  special  features  of  this  trestle  to  which  the  atten- 
tion of  the  student  is  called  are  the  use  of  split  caps,  shown 
in  detail  at  A,  and  the  lateral  bracing  more  distinctly  shown 
in  the  plan.  The  split  caps,  being  but  half  the  size  of  ordi- 
nary caps,  may  be  had  in  better  timber  at  less  cost,  and  may 
be  renewed  without  in  any  way  interfering  with  traffic.  The 
smaller-sized  timbers,  on  account  of  their  thorough  and 
rapid  seasoning,  are  less  liable  to  suffer  from  dry  rot,  and 
being  of  comparatively  small  weight,  they  are  easily  and 
cheaply  handled.  It  is  a  common  practice,  where  split  caps 
are  used,  to  make  the  tenons  at  the  end  of  the  pile  G  inches 
in  thickness.     So  great  a  thickness  is  unnecessary,  and  where 


RAILROAD   STRUCTURES. 


1239 


the  piles  are  under  14  inches  in  thickness  the  shoulder  left 
for  the  cap  to  rest  upon  is  entirely  too  small.     A  tenon  3 


inches  in  thickness  is  ample  and  insures  a  shoulder  of  ample 
width.  The  stringer  joint  is  shown  in  detail  at  B,  The 
stringers  are  not  notched  over  the  caps,  but  are  sized  with 


1240  RAILROAD    STRUCTURES. 

an  adz  to  a  uniform  thickness.  Large  timbers  are  certain 
to  vary  from  ^  inch  to  \  inch  in  thickness;  hence,  the  neces- 
sity of  sizing.  The  notching  of  the  stringers  would  prevent 
the  removal  of  a  cap  unless  the  stringer  was  raised  for  the 
purpose. 

DIMENSIONS    OF    TIMBERS. 

Floor  System  : 

Guard-rails,  8  in.  x  8  in.,  notched  1  in.  over  ties. 
Ties,  7  in.  X  8  in.,  notched  1  in.  over  stringers. 
Stringers,  8  in.  x  10  in.  x  24  ft. 
Bents:     Caps,  6  in.  X  12  in.  X  24  ft. 
Sway-braces,  3  in.  X  10  in. 
Piles,  12  in.  in  diameter. 
Lateral  Braces :     6  in.  x  6  in. 

DIMENSIONS    OF    IRON    DETAILS. 

Bolts:     -^  in.  X  10  in. ;  splicing  guard-rails. 

f  in.  X  32  in.  ;  guard-rails  to  ties  and  stringers. 

f  in.  X  20  in. ;  through  stringers  at  separators. 

f  in.  X  18  in.  ;  caps  to  piles. 

^  in.  X  14  in. ;  at  intersections  of  lateral  braces. 
Drift-bolts  :     f  in.  X  24  in. ;  stringers  to  caps. 


STANDARD  FRAME  TRESTLE,  OREGON   AND  IVASHINGTON 

RAILROAD. 

1794.  High  trestles  furnish  opportunity  for  construct- 
ive skill  and  judgment  of  a  high  order.  Methods  of  con- 
structing trestles  of  this  class,  as  of  others,  have  changed 
much  in  recent  years.  More  iron  is  introduced  and  less 
framing.  Posts  and  sills  are  fastened  together  with  dowels 
instead  of  with  mortise  and  tenon;  braces  are  fastened  with 
bolts,  and,  wherever  possible,  the  cutting  of  timber  incident 
to  framing  is  avoided.  The  braces  are  increased  in  size  and 
reduced  in  number.  Instead  of  short  braces  framed  into  the 
posts  at  each  angle,  long  braces,  reaching  from  one-half  to 
the  total  width  of  the  bent,  are  bolted  to  the  main  tmibers. 
By  this  means,  the  strains  due  either  to  the  wind  pressure  or 
the  train  load  are  distributed  throughout  the  structure. 


RAILROAD   STRUCTURES. 


1241 


The  trestle  shown  in  Fig.  G27  is  a  copy  of  one  built  on  the 
line  of  the  Oregon  and  Washington  Railroad.  Its  height 
from  ground  to  rail  is  about  100  feet,  and  for  simplicity  and 


Fig.  627. 


strength  of  design  it  has  no  superior.  By  battering  the 
inside  posts,  the  load  is  well  distributed  over  the  base,  which 
has  sufficient  breadth  to  insure  stability.     The  system  of 


1242  RAILROAD   STRUCTURES. 

sway-bracing  is  exceptionally  good.  The  horizontal  wales 
a,  b,  and  c,  which  are  bolted  to  the  posts,  practically  double 
the  number  of  decks  and  reduce  the  post  lengths  to  one-half 
their  actual  length.  They  also  form  seats  for  the  purlins  d,  /, 
and  h. 

Each  bent  consists  of  three  sections  of  equal  height, 
separated  by  eight  12  in.  X  12  in.  purlins,  r,  g.  These  pur- 
lins extend  longitudinally  the  length  of  two  bents,  breaking 
joints  like  stringers,  and  form  decks  upon  which  the  succes- 
sive sections  rest.  The  purlins  are  notched  down  1  inch  on 
the  caps,  and  are  also  notched  1  inch  to  receive  the  sills  of 
the  bent  resting  upon  them.  The  caps  and  sills  of  succeed- 
ing sections  are  bolted  together.  The  purlins  constitute 
the  entire  longitudinal  bracing,  excepting  in  the  upper 
section,  where  diagonal  braces  k,  I  are  employed.  It 
would  add  considerably  to  the  stability  of  the  structure  if 
similar  braces  were  placed  in  every  panet  from  the  ground 
upwards.  The  plan  shows  but  one  dowel  at  each  connection 
of  post  with  sill.  Two  would  be  a  better  number,  especially 
in  the  case  of  the  outside  batter  posts  and  the  counter  posts 
7«,  «,  <7,  and/. 

DIMENSIONS    OF    TIMBERS. 

Floor  System  : 

Guard-rails,  10 in.  x  12  in.  and  5  in.  x  8  in.,  notched  1  in. 

over  ties. 
Ties,  G  in.  x  8  in.  x  16  ft.,  notched  1  in.  over  stringers. 
Track  stringers,  9  in.  x  IG  in.  x  32  ft.,  notched  1  in.  over 

caps. 
Jack-stringers,  7  in.  x  IG  in.  X  32  ft. 
Spreaders,  3  in.  X  12  in. 

Bents:  Caps,  12  in.  X  14  in.  x  16  ft. 
Plumb  posts,  12  in.  x  12  in. 
Batter  posts,  12  in.  X  12  in. 
Intermediate  caps  and  sills,  12  in.  x  14  in. 

S^ray-Bracing  :  Horizontal,  6  in.  X  10  in. 
Diagonal,  6  in.  x  10  in. 
Main  sill,  12  in.  x  14  in. 


RAILROAD    STRUCTURES.  1243 

Longitudinal  Bracing:  Horizontal,  0  in.  X  10 in. 

Diagonal,  C  in.  X  10  in. 
Purlins,  12  in.  X  12  in.  X  18  ft. 

DIMENSIONS    OF    IRON    DETAILS. 

Bolts  :  f  in.  X  49  in. ;  floor  system  to  caps. 

f  in.  X  41  in. ;  sills  to  caps  of  different  decks. 

f  in.  X  37  in.  ;  outside  guard-rails  to  jack-stringers 

f  in.  X  27    in.  i  .        -^   a-     ^  u 

:  .  ^,„  .      I  longitudinal  bracing. 

f  in.  X  24|  in.  f        ^  ^ 

f  in.  X  23  in. ;  sway-brace    splice,   sill    splice,    hori- 
zontal sway-bracing  to  posts. 

f  in.  X  22  in. ;  stringer  joints,  packing  bolts. 

f  in.  X  19  in. ;  sway-braces  to  posts. 

f  in.  X  11  in.  ;  inside  guard-rails  to  ties. 
Drift-bolts :   f  in.  X  24  in. ;   sills  to  piles  and  stringers  to 
\  caps. 

Do-wels :  1  in.  X  6  in. ;  posts  to  caps  and  sills. 
Spikes  I  Cut  60-penny ;  spreaders  and  brace  blocks  to  caps. 

Boat,  ^  in.  X  9  in. ;  sway  .-braces  to  posts. 
Cast  Washers :  Under  head  and  nut  of  each  bolt. 


1795.  Practical  Suggestions. — In  practically  all 
trestles  on  American  roads,  designs  have,  either  intentionally 
or  otherwise,  placed  the  stringers  directly  over  the  posts  and 
the  rails  directly  over  the  stringers,  so  that  the  shock  of  the 
passing  train  is  communicated  directly  to  the  post  through 
the  tie  and  stringer,  and  through  the  post  to  the  hard,  un- 
yielding foundation.  The  effect  of  this  can  not  be  other 
than  to  place  unnecessary  stress  upon  particular  timbers, 
and  to  subject  both  rolling  stock  and  foundation  to  unneces- 
sary shock. 

In  most  trestles,  whether  pile  or  framed,  the  stringers  are 
placed  directly  above  the  inside  posts  or  piles,  which  are 
usually  vertical,  and,  consequently,  must  take  practically 
all  the  load  until  from  some  cause  or  other  these  inside  posts 
or  piles  settle,  and  then,  and  not  until  then,  is  a  part  of  the 
load  transferred  through  the  cap  to  the  outside  posts  or 


1244 


RAILROAD   STRUCTURES. 


piles.  It  is  evident  that  if  the  stringers  were  placed  mid- 
way between  the  posts  or  piles,  the  load  would  be  practically 
divided  between  them;  and,  as  there  would  then  be  a  short 
distance  from  the  stringer  to  each  post,  some  of  the  shock, 
at  least,  would  be  taken  up  by  the  cap.  If,  now,  instead  of 
placing  the  stringer  with  its  center  directly  under  the  rail, 
it  were  moved  say  6,  9,  or  12  inches  outwards  from  the 
rail,  the  ties  would  act  partly  as  beams,  and  a  part  of  the 
shock  would  be  taken  up  by  them.  By  arranging  the  posts 
or  piles  as  before  suggested,  a  further  portion  of  the  shock 
would  be  taken  up  by  the  cap.  leaving  a  much  smaller  pro- 
portion of- it  to  be  transferred  by  the  posts  to  the  founda- 
tion, and,  through    recoil,  to  the   passing  train.     Now,  if 


Jlfbtch 


1 "^'^ k^ 


ijfotch 


tie.  628. 


under  the  present  system  the  great  share  of  the  load  is 
carried  (and,  apparently,  with  safety)  by  the  vertical  posts, 
would   not  an  equal  load  be  carried  with  equal  safety  by 


RAILROAD   STRUCTURES.  1245 

smaller  timbers  so  arranged  that  each  shall  perform  its  full 
proportion  of  work  ? 

In  iron  bridges  the  floor  system  is  so  arranged  that  the 
ties  shall  act  as  beams,  and  there  is  no  reason  why  the  floor 
system  of  a  trestle  bridge  should  not  be  arranged  in  the 
same  way.  The  only  objection  to  moving  the  stringers 
from  under  the  rail  is  that  in  case  of  derailment  the  weight 
of  the  derailed  engine  or  car  would,  through  the  wheels,  be 
concentrated  upon  only  a  few  ties.  To  obviate  this  danger, 
or,  at  least,  greatly  reduce  it,  the  ties  should  be  placed  near 
together,  with  not  more  than  G  inches  of  clear  space  be- 
tween them.  This  would  practically  form  a  solid  floor, 
upon  which,  the  wheels  would  run  without  danger  of  biincJi- 
ing  the  ties.  The  guard-rail  should  be  not  more  than  12 
inches  from  the  rail,  and  should  be  not  less  than  7  in.  x  8 
in.  in  cross-section,  notched  1  inch  over  the  ties,  and  bolted 
to  at  least  every  fourth  tie.  With  such  an  arrangement  of 
parts,  posts,  caps,  and  sills  10  in.  X  10  in.  in  cross-section 
would  meet  every  requirement. 

1 796.  A  trestle  plan  embodying  these  ideas  is  given  in 
Fig.  628,  and  recommended  to  the  student  for  practical 
study  and  work.  From  the  plan  it  will  be  seen  that  in  case 
of  derailment,  so  long  as  the  guard  timbers  hold,  the  out- 
side wheels  of  the  derailed  trucks  will  bear  directly  upon  the 
stringer,  which  absolutely  insures  the  ties  against  breaking. 
The  ties,  being  strongly  supported  at  both  ends,  can  not  be 
broken  by  the  inside  wheels  of  the  derailed  trucks,  unless 
they  are  weakened  by  decay.  To  prevent  bunching,  the 
ties  must,  as  stated  above,  be  placed  so  close  together  that 
derailed  wheels  will  roll  over  them.  The  caps,  posts,  and 
sills  are  considerably  smaller  than  those  used  on  most  rail- 
roads, special  exception  being  made  in  the  case  of  the  Penn- 
sylvania Railroad,  already  noted.  The  stringers,  on  the 
other  hand,  are  increased  in  section  from  8  in.  x  10  in.,  a 
size  widely  adopted,  to  9  in.  X  16  in.,  and  are  amply  strong 
for  spans  of  14  feet.  The  guard-rails  are  also  increased  in 
size  above  that  generally  employed.      The    caps  and    sills 


124r,  RAILROAD    STRUCTURES. 

extend  in  length  but  7  inches  beyond  the  batter  posts ;  where- 
as, many  standards  call  for  an  extension  of  from  12  to  18 
inches.  Mortises  and  tenons  are  ;}  in.  X  5  in.  X  7  in.,  with 
treenails  of  either  white  oak  or  locust.  In  pile  trestling, 
the  piles  will  be  spaced  precisely  as  the  posts  in  the  framed 
structure. 

FRAMED    TRESTLE. 

DIMENSIONS    OF    TIMBERS. 

Floor  System  : 

Guard-rails,  8  in.  x  8  in.  X  20  ft.,  notched  1  in.  over  ties. 
Ties,  7  in.  X  8  in.  x  10  ft.,  notched  1  in.  over  stringers. 
Stringers,  9  in.  x  10  in.  X  28  ft.,  notched  1  in.  over  caps. 
Bents:  Caps,  10  in.  X  10  in.  x  13  ft. 
.Plumb  posts,  10  in.  X  10  in. 

Batter  posts,  10  in.  x  10  in. 

Sway-braces,  3  in.  x  10  in. 

Sill,  10  in.  X  10  in. 

DIMENSIONS    OF    IRON    DETAILS. 

Bolts:  f  in.  X  15^  in. ;  guard-rails  to  ties,  a   bolt  in  every 
fourth  tie. 

f  in.  X  21^  in.  ;  through  stringers  at  separators. 

J  in.  X  15^  in. ;  sway-braces  to  cap  and  sill. 
Drift-bolts :  J  in.  diam.  X  23-in.  stringers  to  caps. 
Treenails :   1  in.  X  10  in. 


SIMPLE  WOODEN  TRUSS  BRIDGES. 

1797.  The  period  of  construction  is  a  trying  one  to 
even  the  strongest  companies,  and  any  expenditure  which 
can  either  be  avoided  or  put  off  until  this  trying  period  is 
past  should  not  be  incurred.  This  will  explain  why  so  many 
wooden  structures  are  erected  on  newly  constructed  lines, 
instead  of  those  composed  of  iron  and  steel. 

Three  forms  of  trusses  will  be  considered  in  this  chapter, 
though  only  the  last  is  employed  for  bridges  for  standard 
gauge  railroads.  The  first  and  second  forms  are  suited 
to  bridges  for  narrow-gauge  railroads,  street-car  lines,  and 
highways. 


./  RAILROAD    vSTRUCTURES.  1247 

jr       The  parts  will  be  proportioned  for  the  maximum  loads  to 
'       which  they  will  be  subjected;   and,  instead  of  the  concen- 
trated wheel  loads,  the  equivalent  live  and  dead  loads  per 
lineal  foot  of  span  will  be  used. 

Before  commencing  the  subject  of  trusses,  a  limited  space 
will  be  given  to  the  subject  of  the  materials  entering  into 
these  structures,  their  comparative  strength  and  the  meth- 
ods by  which  the  stresses  upon  the  various  parts  are  deter- 
mined, and  the  parts  proportioned  to  resist  these  stresses. 

1798.  Bridge  Timber. — The  principal  varieties  of 
timiber  used  in  bridge  building  are: 

White  Pine. 

Spruce. 

Long-Leaf  Yellow  Pine. 

Short-Leaf  Yellow  Pine. 

White  Oak. 

Of  these,  long-leaf  yellow  pine,  on  account  of  its  great 
strength  and  the  fact  that  it  may  be  had  in  any  desired  length, 
is  more  used  in  bridge  building  than  the  other  four  varieties 
combined.  On  the  Pacific  Slope,  Washington  fir  is  first  in 
demand,  and  by  most  engineers  it  is  considered  superior  to- 
the  long-leaf  pine. 

1799.  Forces  Operating  in  Bridges.  — The  forces 
to  which  the  timber  in  a  bridge  is  subjected  manifest  them- 
selves in  shearing,  crushing,  bending,  and  breaking.  These 
forces  the  student  has  already  become  familiar  with  in  his 
study  of  the  subject  of  Strength  of  Materials. 

1800.  Transverse    Strength  of  Materials. — The 

transverse  strength  of  a  material  is  that  by  which  it  resists 
breaking.  Now,  it  has  been  determined  by  actual  experi- 
ment that  in  beams  of  the  same  material  and  exactly  alike 
except  in  breadth,  their  strengths  vary  in  the  same  propor- 
tion as  those  breadths,  i.  e.,  if  one  is  two,  three,  or  ten 
times  broader  than  the  other,  its  strength  will  be  two,  three, 
or  ten  times  as  great.      If  they  are  alike  except  in  their 


1248  RAILROAD    STRUCTURES. 

lengths^  their  strength  will  vary  inversely  as  their  lengths, 
i.  e.,  if  one  is  two,  three,  or  ten  times  as  long  as  another,  it 
will  be  only  one-half,  one-third,  or  one-tenth  as  strong.  If 
they  are  alike  except  in  point  of  depth,  their  strengths  will 
vary  as  the  square  of  those  depths,  i.  e.,  if  one  has  a  depth 
two,  three,  or  ten  times  that  of  another,  it  will  be  four,  nine 
or  one  hundred  times  as  strong.  From  this  it  follows  that 
the  strength  of  any  beam,  of  any  size,  of  any  material,  is  in 
proportion  to 

its  breadth  in  inches  X  square  of  its  depth  in  inches 
its  length  in  feet  ' 

and  if  we  find  by  actual  trial  what  center  load  will  break  a 
beam  of  known  size,  and  then  find  the  ratio  between 

its  breadth  in  inches  x  square  of  its  depth  in  inches 
its  length  in  feet 

and  its  breaking  load,  this  ratio  will  be  that  which  any 
similar  beam  of  the  same  material  has  to  its  breaking  load. 
For  example,  if  we  take  a  piece  of  sound,  straight-grained 
spruce,  4  inches  broad  and  8  inches  deep,  and  place  it  hori- 
zontally upon  two  supports  8  feet  apart,  we  shall  find  by 
gradually  loading  the  beam  at  its  center  that  the  breaking 
load,  including  half  the  weight  of  the  beam  itself,  is  14,400 
lb.     Substituting  these  given  dimensions  in  the  fraction 

the  breadth  in  inches  X  square  of  the  depth  in  inches 
length  in  feet  ' 

4  X  64 
we  have —  =  32,    and    the   ratio    between    14,400  and 

o 

14  400 
32  =  — '— —  =  450.     This  ratio  is  called  the  constant   for 

the  center  breaking  load   for  beams  of  spruce,  and   to  find 

the  center  breaking  load  for  any  beam  of  the  same  material 

we  take  its  dimensions  and  substitute  them  in  the  following 

formula : 

breadth  in      sjuarc  of  depth 

,       ,  .       ,      ,  inches  tn  inches  „ 

center  oreaking  load  — 7— — —. 7-- X  C. 

length  tn  feet  (127.) 


RAILROAD   STRUCTURES.  1249 

In  this  formula,  6^  is  a  constant  depending  on  the  kind  of 
timber,  and  its  value  for  four  of  the  most  commonly  used 
varieties  is  given  in  Table  52. 

Example. — A  spruce  beam  is  8  in.  broad,  12  in.  deep,  and  20  ft.  long; 
what  is  its  center  breaking  load  ? 

Solution. — Substituting  the  given  dimensions  in  the  above  for- 
mula, we  have,  using  the  value  for  C  given  in  Table  52  for  spruce, 

8  X  144 
center  breaking  load  =  — ^ —  x  450  =  25,920  lb.     Ans. 

One-half  the  weight  in  pounds  of  the  beam  itself  must  be 
deducted  from  this  result  to  obtain  the  neat  center  load. 

1801.  Factor  of  Safety. — In  order  that  a  structure 
may  endure,  no  part  of  its  framework  should  be  strained  to 
the  limit  of  its  strength.  The  ratio  between  the  ultimate 
or  breaking  load  of  a  beam  and  the  working  load,  which  is 
the  actual  load  placed  upon  it,  is  called  the  factor  of  safety. 
This  factor  of  safety  will  vary,  according  to  the  character  of 
the  structure  and  the  nature  of  the  strains  to  which  it  will 
be  subjected.  Roof  trusses  which,  except  in  cases  of  violent 
storms,  support  a  quiescent  load  consisting  of  the  roof  cover- 
ing, snow,  ice,  etc.,  together  with  their  own  weight,  may 
have  a  factor  of  safety  as  low  as  3.  But  for  bridges,  espe- 
cially those  carrying  locomotives  and  heavy  trains,  where 
the  strains  are  sudden  and  violent,  a  factor  of  safety  of  at 
least  6  should  be  used;  and  for  those  on  important  lines,  a 
factor  of  8  is  none  too  great.  Hence,  in  the  preceding  ex- 
ample, the  beam  whose  ultimate  center  load  is  25,920  lb.,  if 
used   in  a  railroad  bridge,   should   not  be  subjected   to  a 

25  920 
greater  center  load  than  — ^ —  =  4,320  lb. 

1802.  Table  of  Constants. — By  actual  experiment, 
not  only  with  small  specimens  of  timber  (usually  1  inch 
square  and  12  inches  between  supports),  but  with  full-sized 
beams,  the  center  breaking  loads  for  many  varieties  of  tim- 
ber and  their  constants  have  been  determined.  The  varieties 
of  timber  most  used  in  bridge  building,  together  with  their 


1250  RAILROAD    STRUCTURES. 

constants  for  center  breaking  loads,  are  given  in  the  follow- 
ing table.  For  highway  bridges,  use  a  factor  of  safety  of 
5;  for  street  car  bridges,  a  factor  of  6,  and  for  railroad 
bridges,  a  factor  of  7  or  8 : 

TABLE    52. 


CONSTANTS    FOR    CROSS    HRBAKING    CENTER    LOADS. 


Material. 

Pounds. 

Hemlock 

400 

White  Pine  and  Spruce     

450 

Southern  Long-Leaf  Yellow  Pine 

550 

White  Oak 

600 

1803.  Inclined  Beams. — When  the  beam,  instead  of 
being  horizontal,  is  inclined,  the  horizontal  distance  between 
the  points  of  support  must  be  taken  as  the  span. 

1804.  To  find  tlie  side  of  a  square  horizontal 
beam  of  given  span,  supported  at  both  ends  and 
required  to  break  under  a  given  quiescent  center 
load  : 

YlviW.  —  Multiply  the  clear  span  in  feet  by  the  given  break- 
ing load  in  pounds.  Divide  the  product  by  the  corresponding 
constant^  Art.  1802.  Take  the  cube  root  of  the  quotient. 
This  cube  root  ivill  be  the  required  breadth  or  depth  of  the 
beam,  approximately,  in  inches. 

When  the  size  of  the  beam  is  so  great  that  its  weight 
must  be  taken  into  consideration,  provide  for  this  addi- 
tional weight  by  increasing  the  size  of  the  beam  as  follows: 
Calculate  the  weight  of  the  beam  already  obtained  Then 
say,  as  the  center  load  is  to  half  this  weight,  so  is  the  breadth 
found  to  a  neiu  breadth  to  be  added  to  it.     It  will  still  be 


RAILROAD    STRUCTURES.  1251 

somewhat  too  small,  owing  to  the  weight  of  the  breadth 
last  added.  This  additional  weight  may  be  easily  found 
and  provided  for  by  adding  to  the  breadth. 

Example. — What  is  the  side  of  a  square  horizontal  white  pine  beam, 
12  ft.  long  between  supports,  which  will  break  under  a  quiescent  center 
load  of  50,000  lb.  ? 

Solution.— 50,000  X  13  =  600,000;  600,000  -r-  450,  the  constant  for 
white  pine,  =  1,333.  The  cube  root  of  1,333  is  11,  almost  exactly ;  hence, 
a  horizontal  beam  11  inches  square  and  12  feet  between  supports  will 
break  under  a  quiescent  center  load  of  50,000  lb.     Ans. 

In  this  case,  no  account  is  taken  of  the  weight  of  the 
beam,  which  is  so  small  in  comparison  to  its  center  breaking 
load  that  it  may  be  ignored. 

1805.  To  find  the  side  of  a  square  horizontal 
beam  which  will  safely  bear  a  given  center  load  : 

Rule. — Multiply  the  given  load  by  the  number  of  times  it 
is  exceeded  by  the  breaking  load.  Then  find  by  Art.  1804  the 
side  of  a  square  beam  to  break  under  this  increased  load.  The 
beam  thus  found  will  be,  approximately.^  the  safe  one  for  the 
actual  load,  exclusive  of  the  weight  of  the  beam  itself.  If 
this  weight  must  be  included,  provide  for  it  by  increasing  the 
breadth,  as  directed  in  A  rt.  1804. 

Example. — What  should  be  the  side  of  a  square  beam  of  white  pine 
placed  horizontally  with  10  feet  between  supports  to  safely  bear  a 
center  load  of  12,000  lb.,  with  a  factor  of  safety  of  6  ? 

Solution.— 12,000  lb.  X  6  =  72,000  lb.,  the  center  breaking  load  for 
the  beam.  72,000x10  =  720,000.  720,000^-450,  the  constant  for 
center  breaking  loads  for  white  pine,  =  1,600.  The  cube  root  of 
1,600  =  11.7.  Hence,  the  side  of  the  square  is  11.7  in.  Ans.  By 
increasing  the  side  of  the  square  to  12  inches,  we  make  ample  allow- 
ance for  the  additional  weight  of  the  beam. 

1806.  To  find  the  breadth  of  a  horizontal  rect- 
angular beam,  supported  at  both  ends,  to  break 
under  a  given  quiescent  center  load,  the  span  and 
depth  of  beam  being  given  : 

Rule. — Multiply  the  center  load  in  pounds  by  the  span  in 
feet.     Multiply  the  square  of  the  depth   in   inches   by   the 


1252  RAILROAD    STRUCTURES. 

constant^  Art.  1802.      Divide  the  first  product  by  the  last. 
The  quotient  will  be,  approximately.,  the  breadth. 

If  the  weight  of  the  beam  is  so  great  that  it  need  be 
taken  into  consideration,  provide  for  this  increased  weight 
by  increasing  the  size  of  the  beam,  as  directed  in  Art. 
1804. 

Example. — A  horizontal  beam  of  yellow  pine  is  18  ft.  between  sup- 
ports; the  depth  of  the  beam  is  12  in. ;  what  should  be  the  breadth  of 
the  beam  to  break  under  a  quiescent  center  load  of  50,000  lb.  ? 

Solution.— 50,000  x  18  =  900.000  lb.  The  constant  for  the  breaking 
center  load  of  yellow  pine  is  550  (Art  1802).  The  depth,  12, 
squared  =  144;'144  x  550  =  79,200;  900,000  -^  79,300  =  11.36,  the  breadth 
of  the  required  beam.  Ans.  By  increasing  the  breadth  to  12  inches, 
the  increased  center  load  due  to  the  weight  of  the  beam  itself  is  more 
than  provided  for. 

1807.  To  find  the  depth  of  a  horizontal  rect- 
angular beam,  supported  at  both  ends,  which 
shall  break  under  a  given  quiescent  center  load, 
the  breadth  of  the  beam  and  length  of  span  being 
given  : 

Rule. — Multiply  the  load  in  pounds  by  the  span  in  feet. 
Multiply  the  breadth  in  inches  by  the  consta?it  given  in  Art. 
1802.  Divide  the  first  product  by  the  last ;  take  the  square 
root  of  the  quotient  for  an  approximate  depth.  Calculate 
the  iveight  of  a  beam  having  the  depth  already  found ;  add 
half  its  weight  to  the  given  center  load,  and  ivith  the  new 
load  repeat  the  calculation  ;  the  result  will  be  close  enough 
for  practical  purposes,  though  not  exact,  ozving  to  the  neg- 
lect of  the  iveight  of  the  depth  last  added. 

Example. — A  rectangular  horizontal  beam  of  yellow  pine  is  9  in. 
broad  and  16  ft.  between  supports;  what  should  be  the  depth  of  the 
beam  to  break  under  a  quiescent  center  load  of  24,000  lb.  ? 

Solution.— 24,000  x  16  =  384,000  lb.  The  constant  for  yellow  pine 
(Art.  1 802)  is  550.  550  x  9  ^  4,950.  384,000  -h  4.950  =  77.57.  ^^77:57  = 
8.8  in.  A  beam  of  these  dimensions,  viz..  9  in.  X  8  8  in.  X  16  ft.,  will 
contain  15,206  cu.  in  =  8.8  cu.  ft.  Yellow  pine  weighs  on  an  average 
45  lb  per  cu.  ft.  Hence,  the  beam  weighs  45  X  8.8  =  396  lb.  396  -h  2  ^ 
198  lb.,  which,  added  to  24.000  lb.,  the  given  center  load,  gives  24,198, 


RAILROAD   STRUCTURES.  1253 

the  total  center  load  of  the  beam.  24,198x16  =  387,168.  387,168^ 
4,950  =  78.22,  the  square  root  of  which  is  8.84,  the  required  depth  of 
the  beam  in  inches.     Ans. 

From  this  result  the  student  will  see  that  in  providing 
for  the  weight  of  the  beam  the  depth  of  the  beam  is 
increased  only  .0-i  inch,  an  amount  so  small  that  it  may  be 
ignored.  In  actual  practice  this  depth  would  be  increased 
to  9  inches. 

1 808.  Strength  of  IVooden  Pillars. — The  strength 
of  wooden  pillars,  like  that  of  wooden  beams,  depends 
much  upon  their  degree  of  seasoning.  Thoroughly  seasoned 
sticks  will  often  support  twice  as  great  a  load  as  green 
ones.  This  fact  should  be  borne  in  mind  when  erecting 
structures  of  imperfectly  seasoned  timber.  For  permanent 
structures,  timber  should  not  be  subjected  to  more  than 
from  ^  to  1^  of  its  crushing  load. 

The  following  formula  by  Charles  Shaler  Smith  is  for 
the  breaking  loads  of  square  or  rectangular  pillars  or  posts 
of  moderately  seasoned  white  or  yellow  pine,  with  flat  ends, 
firmly  fixed  and  equally  loaded: 

Calling  either  side  of  the  square  or  the  least  side  of  the 
rectangle  the  breadth,  we  have 

Breaking  load  in  pounds  per  square  inch  of  area  of  pillar 
of  white  or  yellow  pine  = 

5,000 

^       /square  of  the  length  in  inches  ^  V  /j  28.) 

\  square  of  breadth  in  inches  )  ' 

in  which  5,000  equals  the  breaking  load  in  pounds  per 
square  inch  for  short  blocks. 

Example. — A  pillar  of  white  pine  is  10  inches  square  and  8  feet  long; 
what  is  its  safe  load  with  a  factor  of  safety  of  6  ? 

Solution.— The  length  equals  8  f t.  =  96  in.  96-^  =  9,216.  The 
square  of  the  breadth  =  10'^  =  100.  Applying  the  given  formula,  we 
have 

Breaking  load  in  pounds  per  square  inch  of  area  = 
5,000  5,000 


9,216        ^.\  ~  1.37 


..C^^x.-x.) 


=  3,650  lb. 


1254  RAILROAD    STRUCTURES. 

As  this  is  the  breaking  load,  and  a  factor  of  6  is  required,  the  safe 
load  per  square  inch  will  be  3,650^6  =  608  lb.,  nearly,  and  for  100 
square  inches,  the  area  of  the  pillar,  the  safe  load  will  be  608  X  100  = 
60,800  lb.     Ans. 

Example. — A  rectangular  pillar  is  8  in.  x  10  in.  x  12  ft. ;  what  is  its 
safe  load  with  a  factor  of  safety  of  4  ? 

Solution. — Applying  the  above  formula,  we  have 

Breaking  load  in  pounds  per  square  inch  of  area  = 

5,000  5,000 


1       /144'         --,     ~    2.3 


=  2,174  lb., 


the  breaking  load  per  square  inch.  With  a  factor  of  safety  of  4,  we 
find  the  safe  load  to  be  2,174  -h  4  =  543  lb.  per  sq.  in.  The  area  of  the 
pillar  is  8  X  10  =  80  sq.  in. ,  and  543  X  80  =  43,440  lb.     Ans. 

In  applying  this  formula  to  composite  columns,  made  up 
of  several  sticks  bolted  together  at  intervals,  give  to  each 
stick  its  proportionate  share  of  the  total  load  to  be  carried 
by  that  member,  and  then  assume  that  it  stands  alone  and 
unsupported.  This  is  the  only  safe  rule.  Even  though 
the  sticks  are  firmly  bolted  together  with  packing-blocks 
notched  into  the  sides,  they  should  never  be  assumed  to  act 
as  one  solid  stick,  as  the  packing-blocks  and  washers  are 
sure  to  grow  loose  in  time. 

1809.  Shearing  and  Crushing. — For  shearing  and 
crushing  it  is  generally  safe  to  use  a  factor  of  safety  of 
2  or  3.  Use  for  working  values  of  the  shearing  stress  along 
the  grain ^  for 

White  pine  and  spruce 200  lb.  per  sq.  in. 

Long-leaf  yellow  pine 400  lb.  per  sq.  in. 

Short-leaf  yellow  pine. 300  lb.  per  sq.  in. 

White  oak 600  lb.  per  sq.  in. 

For  crushing  across  the  grain,  take  for  working  values  of 
seasoned  timber,  for 

White  pine  and  spruce 300  lb.  per  sq.  in. 

Long-leaf  yellow  pine 500  lb.  per  sq.  in. 

Short-leaf  yellow  pine 450  lb.  per  sq.  in. 

White  oak 1,000  lb.  per  sq.  in. 


RAILROAD    STRUCTURES.  1255 

For  crushing  endivisc  (short  blocks),  take  for  working 
values  for 

White  pine 2,500  lb.  per  sq.  in. 

Long-leaf  yellow  pine 3,000  lb.  per  sq.  in. 

Short-leaf  yellow  pine 2,800  lb.  per  sq.  in. 

White  oak   2,750  lb.  per  sq.  in. 

1810.  Tension. — Wood  fiber  is  much  stronger  in  ten- 
sion than  in  any  other  way,  and,  as  a  result,  it  may  be  said 
that  wood  seldom  or  never  breaks  in  pure  tension  in  actual 
service.  In  long  sticks  in  tension,  the  grain  runs  more  or 
less  across  the  line  of  the  stick,  and  a  liberal  allowance  must 
be  made  for  the  reduction  of  the  stick  by  framing  it.  In 
actual  work,  it  is  not  well  to  rely  upon  a  working  stress  in 
tension  of  more  than  2,000  or  3,000  pounds  per  square  inch 
for  ordinary  bridge  timber. 


EXAMPLES  FOR  PRACTICE. 

1.  A  stick  of  white  pine  is  subjected  to  a  shearing  stress  along  the 
grain  of  40,000  lb. ;  how  many  square  inches  of  surface  are  necessary  to 
sustain  this  stress  with  a  factor  of  safety  of  3  ? 

Solution. — From  Art.  1809,  we  find  the  safe  working  value  for 
shearing  stress  per  square  inch  along  the  grain  for  pine  is  200  lb.,  and 
to  sustain  a  stress  of  40,000  lb.,  it  will  require  as  many  square  inches  of 
surface  as  200  is  contained  in  40,000,  which  is  200  sq.  in.     Ans. 

2.  An  oak  tie-beam  is  subjected  to  a  shearing  stress  across  the  grain 
of  62,000  lb.;  how  many  square  inches  of  surface  are  necessary  to 
sustain  this  stress?    Ans.  103.3  sq.  in. 


1811.  To  find  tlie  safe  dimensions  for  a  rectan- 
gular horizontal  beam  of  jriven  span,  supported  at 
both  ends,  and  which  is  at  the  same  time  subjected 
both  to  a  transverse  strain  and  to  a  longitudinal 
tensile  or  pulling  one,  or  to  a  longitudinal  com- 
pressive one  : 

Rule. —  When  the  longitudinal  strain  is  tensile,  ^nd  sepa- 
rately the  safe  dimensions  as  if  for  a  beam  alone,  and  as  if 
for  a  tie  alone,  and  add  the  ttvo  resulting  areas  together. 
When  the  lo?igitudinal  strain  is  eompressive,  find  separately 


1250 


RAILROAD    STRUCTURES. 


»= 


Plunk. 


TJs: 


h 


3x8 


3x8  Separaton. 
k 


J 5* 


UI 


ill! 


r' 


1: 


B 


^m-k 


Fig.  629. 


RAILROAD   STRUCTURES.  1257 

the  safe  dimensions  as  if  for  a  beam  alone,  and  as  if  for  a 
pillar  alone,  and  add  the  two  resulting  areas  together. 

Example. — A  rectangular  horizontal  beam  of  yellow  pine  of  14  feet 
span  is  to  sustain  a  uniformly  distributed  transverse  load  of  40,000  lb., 
and  a  pulling  stress  of  30,000  lb. ,  with  a  factor  of  6 ;  what  should,  be  the 
dimensions  of  the  beam  ? 

Solution. — A  uniformly  distributed  load  of  40,000  lb.  is  equivalent 
to  a  center  load  of  20,000  lb.  A  safe  center  load  of  20,000  lb.  with  a 
factor  of  6  is  equivalent  to  a  center  breaking  load  of  120,000  lb.  Apply- 
ing the  rule  given  in  Art.  1804,  we  have  120,000x14  =  1,680,000. 
The  constant  for  center  breaking  loads  for  yellow  pine  (Art.  1802)  is 
550.  1,680,000-^550  =  3,054,  the  cube  root  of  which  is  14. 5.  This  gives 
in  inches  the  side  of  a  square  beam  which  will  safely  carry  the  given 
load. 

From  Art.  1810  we  conclude  the  safe  working  stress  in  tension  per 
square  inch  for  yellow  pine  to  be,  say  3,000  lb.  per  square  inch.  The 
given  tensile  stress  is  30,000  lb.,  to  resist  which  it  will  require  as  many 
square  inches  as  3,000  is  contained  in  30,000,  which  is  10.  We,  there- 
fore, add  10  sq.  in.  to  area  of  the  given  beam  by  increasing  either  the 
breadth  or  depth  -^^  of  an  inch.     Ans. 

1812.  Bridge  Loads. — The  trusses  will  be  propor- 
tioned for  the  following  loads,   viz : 

Highway  bridges,  combined  live  and  dead  load  equivalent 
to  1,500  pounds  per  lineal  foot. 

Street  car  bridges,  combined  live  and  dead  load  equivalent 
to  4,000  pounds  per  lineal  foot. 

Railroad  bridges,  combined  live  and  dead  load  equivalent 
to  6,000  pounds  per  lineal  foot. 

The  foregoing  are  the  maximum  loads  to  which  they  will 
be  subjected. 

The  forms  of  trusses  given  will  not  be  used  for  spans  ex- 
ceeding 30  feet  for  railroads,  or  40  feet  for  highways.  Where 
larger  spans  occur,  other  and  more  complicated  forms  of 
trusses  will  be  employed,  the  designing  of  which  properly 
belongs  to  the  bridge  department. 

1813.  King-Rod  Truss. — The  simplest  form  of  a 
bridge  truss  is  shown  in  Fig.  029.  This  is  called  a  king-rod 
truss,  from  the  rod  a  b,  which  extends  from  the  head  a  of  the 
ratters  to  the  base  /)  of   the  needle-beam  c.     Heavy  cast 


1258  RAILROAD   STRUCTURES. 

washers  are  placed  under  both  head  and  nut  of  the  king-rod, 
and  when  the  nut  is  tightened,  ail  parts  of  the  truss  are  put 
under  strain. 

Let  </,  d  be  points  half  way  between  the  king-rod  and  the 
abutments  %i\  w\  then,  the  king-rod  a  b  will  sustain  all  the 
weight  resting  upon  the  beam  e  f,  between  the  points  d^  d\ 
also,  half  the  weight  of  the  needle-beam  c,  and  of  the  load 
resting  upon  it.  From  an  inspection  of  the  plan,  it  will  be 
readily  seen  that  all  that  portion  of  the  bridge  between  the 
points  d^  d  and  the  abutments  w,  w  is  supported  by  the  abut- 
ments. The  entire  weight  of  the  truss  and  its  load  is  sus- 
tained ultimately  by  the  abutment  walls,  but  the  portion  d,  d 
reaches  them  by  first  traveling  up  the  king-rod  a  b  \.o  the 
head  of  the  rafters  and  then  down  them  to  their  feet,  where 
it  is  transmitted  directly  to  the  abutments. 

From  an  inspection  of  the  plan,  it  will  be  readily  seen 
that  all  of  the  floor-beams  g,  h,  i,  k,  I,  m,  and  n  rest  upon 
the  needle-beam,  and,  instead  of  one  span  of  20  feet,  they 
form  two  spans  of  10  feet  each,  which  permits  us  to  use 
much  smaller  floor-beams  than  would  be  required  for  a  span 
of  20  feet.  Assuming  that  the  total  dead  load  (i.  e.,  the  load 
of  the  structure  itself)  and  the  live  load  (i.  e.,  the  load 
placed  upon  the  bridge,  but  distinct  from  the  weight  of  the 
structure  itself)  are  equivalent  to  100  lb.  per  sq.  ft.  of  bridge 
floor,  we  have  the  total  load  carried  by  two  king -rods  equal 
to  10  X  17  X  100  =  17,000  lb.,  and  for  one  king-rod  the  load 

z 
Let  the  height  of  the  peak  a  of  the  truss  be  G  feet  above 
the  tie-beam  e  f.  Draw  the  rafters  conforming  to  the 
dimensions  given  in  the  plan.  Draw  the  line  a  b,  repre- 
senting the  king-rod,  and  lay  off  upon  it  downwards  from  a' 
to  a  scale  of  10,000  lb.  to  the  inch,  the  distance  a'  o  =  8,500  lb. 
Complete  the  parallelogram  a'  q  o  p  and  draw  the  diagonal 
q  p.  Then  a  p  and  a  q  will  measure  the  stresses  upon 
the  rafters  due  to  the  weight  upon  the  king-rod,  and  r  p 
and  r  q  the  pulling  forces  produced  by  the  same  weight; 
but   they  act  along   the   tie-beams  in  opposite  directions. 


RAILROAD    STRUCTURES.  1259 

causing  a  stress  equal  to  one  of  them  throughout  the  tie- 
beam. 

To  resist  the  stress  «/>  or  a  q,  running  lengthwise  through 
the  rafter  from  head  to  foot,  the  rafter  must  be  regarded  as 
a  pillar^  and  the  safe  area  required  to  resist  this  stress  we 
find  by  applying  formula  128,  given  in  Art.  1808,  viz.: 

Breaking  load  in  pounds  per  square  inch  of  area  of  yellow 

pine  — 

5,000 


^    ,   /  square  of  length  in  inches  ^^A 

1  +  (— ^ ;,      \i,i    ■     ■     1       X  .004) 

\  square  of  breadth  m  inches  J 

The  length  of  rafter  as  measured  along  its  center  line 
from  joint  to  joint  is  11  ft.  6  in.  =  138  in. 

Assuming  a  breadth  of  6  in.  for  the  rafters,  we  have 
Breaking  load  in  pounds  per  square  inch  of  area  = 
5,000 


i-,(f!x.oo.; 


=  1,604  lb., 


which,  with  a  factor  of  safety  of  8,  gives   a   safe  load  of 

1,604       _-_  „ 

-!— —  =  200  lb.  per  sq.  m. 

The   stress   a'  p   measured    by   the    given    scale   equals 
9,000  lb.  ;  hence,  the  area  required  to  resist  this  stress  will 

be    '         =  45  sq.  in.     The  breadth  of  the  rafter  has  been 

45 
assumed   as    6   inches;    hence,    the   depth    must    be    -v^  = 

1\  inches.  Since  the  usual  market  sizes  of  timber  run  only 
in  even  inches,  we  will  make  the  depth  of  the  rafter  8  inches. 
In  this  bridge  the  plank  flooring  does  not  rest  directly 
upon  the  tie-beams,  but  upon  the  floor-beams  g  and  «, 
which  are  spiked  to  the  tie-beams.  The  tie-beams  are 
gained  2  in.  to  form  footings  for  the  rafters,  and  the  tie-rods 
pass  through  them,  reducing  their  actual  span  to  10  ft.,  one- 
half  the  total  span  of  the  bridge.  If  the  tie-beams  were 
given  smaller  dimensions  than  the  rafters,  they  would  appear 
weak,  and,  though  unnecessarily  large,  we  give  them  the 
same  dimensions,  viz.,  6  in.  X  8  in. 


1260  RAILROAD    STRUCTURES. 

We  determine  the  dimensions  of  the  needle-beam  c  by  first 
finding  the  load  which  it  must  sustain.  The  king-rods 
support  the  needle-beam,  which  in  turn  supports  the  tie- 
beams,  floor-beams,  and  floor,  and,  hence,  both  sustain  prac- 
tically the  same  load.  The  total  uniform  load  we  have 
already  determined  to  be  17,000  lb.,  which  is  equivalent  to 
a  center  load  of  8,500  lb.  This  gives,  with  a  factor  of 
safety  of  G,  a  center  breaking  load  of  8,500  X  6  =  51,000  lb. 
The  span  from  center  to  center  of  king-rods  is  16.5  ft. 
Assuming  for  the  needle-beam  a  depth  of  12  in.,  we  have, 
from  Art.  1 806, 

.     ,,         ,.        51,000X16.5      ,.^. 

required  breadth  =         , -— —  =  10.6  m. 

1/i    X  5oO 

As  it  is  safe  to  say  that  the  bridge  will  never  be  loaded 
to  these  limits,  owing  to  the  difficulty  of  loaded  teams  passing 
on  the  bridge,  we  make  the  breadth  of  the  needle-beam  an 
even  10  in. 

The  floor-beams  have  a  clear  span  of  9  ft.  7  in.,  or  9.58  ft. 

The  distance  from  center  to  center  of  floor-beams  is  2  ft. 

8  in.,  or  2.66  ft.     Hence,  the  total  distributed  load  on  each 

beam,  at  100  lb.  per  sq.  ft.,  is  2.66  X  9.58  X  100  =  2,548  lb., 

2  54S 
equal   to    a  center  load  of     '     '  =  1,274   lb.     Allowing  a 

Xi 

factor  of   safety  of   8,   we  have  a  center  breaking  load  of 

1,274  X  8  =  10,192  lb. 

Assuming  for  floor-beams  a  depth  of  8  in.,  we  find  from 

Art.  1806, 

...        ,^,        10,192x9.58      _  ^^  . 

required  breadth  =  — -—^ — — —  =  2.77  in. 

^  8'  X  550 

This  breadth  we  increase  to  3  in.,  the  standard  dimension 
nearest  to  the  one  required,  making  the  cross-section  dimen- 
sion of  the  floor-beams  3  in.  X  8  in.  Their  length  should  be 
equal  to  the  total  length  of  the  bridge,  or  23  ft.  The  floor- 
beams  and  stringers  do  not  come  in  direct  contact  with  the 
stone  abutments,  but  rest  upon  timbers  j,  s,  called  wall 
plates,  by  means  of  which  the  weight  of  the  bridge  is  dis- 
tributed over  the  entire  bridge  seat.     The  wall  plates  are  of 


RAILROAD    STRUCTURES. 


1201 


oak  timber,  4  in.  by  G  in.,  and  extend  the  full  length  of  the 
abutments. 

The  dimensions  of  the  king-rod  may  be  found  in  Table  53. 

TABLE  53. 


WEIGHTS  AND  STRENGTHS  OF  IRON  BOLTS. 


Ends  Enlarged  or  Upset. 

Ends  Enlarged  or  Upset. 

Diam- 
eter of 

Weight  per 

Breaking 

Diam- 
eter of 

Weight  per 

Breaking 

Shank. 

Foot  Run. 

Stress. 

Shank. 

Foot  Run. 

Stress. 

Inches. 

Pounds. 

Pounds. 

Inches. 

Pounds. 

Pounds. 

i 

.661 

8,803 

If 

8.10 

102,368 

tV 

.837 

11,133 

;      Iff 

8.69 

109,760 

f 

1.03 

13,754 

U 

9.30 

117,600 

u 

1.25 

16,621 

m 

9.93 

125,440 

f 

1.49 

19,779 

2 

10.6 

133,728 

1  3 

1.75 

23,296 

H 

12.0 

142,912 

i 

2.03 

26,880 

H 

13.4 

160,384 

H 

2.33 

30,912 

H 

14.9 

178,528 

1 

2.65 

35,168 

n 

16.5 

198,016 

ItV 

2.99 

37,632 

H 

18.2 

218,176 

H 

3.35 

42,336 

2| 

20.0 

239,456 

lA 

3.73 

47,264 

H 

21.9 

261,632 

H 

4.13 

52,192 

3 

23.8 

284,928 

lA 

4.56 

57,568 

H 

27.9 

315,840 

If 

5.00 

63,168 

H 

32.4 

366,464 

ItV 

5.47 

68,992 

3f 

37.2 

420,448 

H 

5.95 

75,264 

4 

42.3 

478,464 

ItV 

6.46 

81,536 

H 

47.8 

508,480 

ll 

6.99 

88,256 

H 

53.6 

570,080 

iH 

7.53 

95,200 

4| 

59.7 

635,040 

The  load  which  each  king-rod  sustains  we  found  to  be 
8,500   lb.     A    rod   which   would    safely   sustain    this  load 


1262 


RAILROAD    STRUCTURES. 


with  a  factor  of  safety  of  0  would  break  under  a  load  of 
8,500  X  G  =  51,000  lb. 

Referring  to  the  table,  we  find  in  the  column  headed 
Breaking  Stress,  the  number  most  nearly  corresponding  to 
51,000,    which  is   52,192   lb.     This   stress   calls   for   a   rod 

1 


RAILROAD    STRUCTURES.  1263" 

1:^  in.  in  diameter,   which  is  the  diameter  we   specify  for 

king-rods. 

The  stress  in  the  rafters  produces  a  shearing  stress  along 

the  grain  of  the  tie-beam  at  the  footing  of  the  rafter.     This 

stress  is  equal  to  r  /,  or  7,800  lb.     We  find  in  Art.  1809 

that    the    working  stress   for    shearing  along  the  grain  in 

yellow  pine  is  400  lb.  per  sq.  in.,  and  to  resist  a  shearing 

7  800 
stress  of  7,800  lb.  it  will  require    '    ^    =  19.5  sq.  in.     There 

400 

must  accordingly  be  sufficient  space  between  the  foot  of  the 

rafter  and  the  end  of  the  stringer  to  give  a  superficial  area 

of  at  least  19.5  in.     As  we  have  made  this  distance  12  in., 

giving   a   superficial  area   of   6x12  =  72  in.,    there  is  no 

question  of  the  security  of  this  joint.     The  bolts  /,  /  passing 

through  the  tie-beam  at  the  foot  of  the  rafter  serve  only  to 

keep  the  rafter  in  place.     The  needle-beam  projects  4  ft.  3  in. 

outside  the  truss,  as  shown  in  detail  2X  A.     A  brace  u  runs 

from  this  projecting  needle-beam  to  the  head  of  the  rafters. 

It  is  fastened  with  spikes,  and  serves  to  stiffen  the  truss  and 

prevent  lateral  vibration. 

The  joint  of  the  rafters  at  their  head,  together  with  king- 
rod  and  washers,  is  shown  in  detail  at  B. 

In  Fig.  630  is  illustrated  another  form  of  the  king-rod 
truss,  in  which  the  stiffeners  a  b,  c  d  are  introduced,  their 
object  being  to  stiffen  the  rafters  and  prevent  their  bending 
under  the  longitudinal  stress  transmitted  to  them  by  the 
king-rod.  The  stiffeners  extend  from  the  middle  of  the 
rafters  to  the  base  of  the  king-rod,  where  they  abut  against 
a  cast-iron  angle  block.  A  cast-iron  socket  is  let  into  the 
rafter  at  the  head  of  each  stiffener,  and  holds  it  securely  in 
place.  The  angle  block  at  the  foot  of  the  king-rod  has  two 
ribs  which  project  1  in.  below  the  base  of  the  block. 
Grooves  are  cut  in  the  tie-beam  to  receive  these  ribs,  which 
hold  the  angle  block  firmly  in  place.  A  hole  is  cast  in  the 
angle  block  through  which  the  king-rod  passes.  The 
stiffeners  practically  reduce  the  length  of  the  rafters  to 
one-half  their  actual  length,  so  far  as  their  sustaining  power 
as  pillars  is  concerned. 


1264  RAILROAD   STRUCTURES. 

The  bridge  shown  in  the  figure  is  to  accommodate  the 
traffic  of  both  street  cars  and  highway.  The  parts  are  pro- 
portioned for  an  equivalent  live  and  dead  load  of  4,000  lb. 
per  lineal  foot  of  bridge.  The  material  is  long-leaf  yellow 
pine.  The  stresses  are  calculated  as  were  those  for  the 
bridge  shown  in  Fig.  G29.  The  clear  span  of  the  bridge  is 
28  ft. ,  and  the  breadth  from  outside  to  outside  of  truss  is 
19  ft.  4  in.,  and  the  height  of  truss  above  the  tie-beams 
is  9  ft.  The  two  king-rods  ^'/support  that  portion  of  the 
bridge  and  its  load  between  the  points  j,  y,  or  together,  one- 
half  the  total  load. 

At  4,000  lb.  per  lineal  foot,  the  load  between  j,  _>/  is 
4,000  X  14=  56,000  lb.,  one-half  of  which,  or  28,000  lb.,  is 
carried  by  each  king-rod.  Accordingly,  we  lay  out  the  out- 
lines of  the  rafters,  and  though  we  do  not  yet  know  their 
depth,  we  can  draw  their  upper  edges,  which  will  not  alter 
their  position,  and  form  two  sides  of  our  parallelogram  of 
forces.  We  next  draw  the  line  e  f^  which  will  be  the  center 
line  of  the  king-rod.  Upon  this  lay  off  from  g,  to  a  scale  of 
20,000  lb.  to  the  inch,  the  distance  ^//^  28,000  lb.  Com- 
plete the  parallelogram  g  I  h  k.  Then  the  equal  sides  g  I 
and  g  k  will  represent  by  the  same  scale  the  longitudinal 
stress  in  the  rafters.  These  stresses,  which  we  find  to  be 
27,300  lb.,  pass  down  the  rafters  and  are  taken  up  by  the 
abutments.  To  resist  these  stresses,  the  rafters  act  as 
pillars.  As  before  stated,  the  stiffeners  a  b  and  c  d  virtually 
reduce  the  length  of  these  pillars,  i.  e.,  the  rafters,  to  one- 
half  their  total  length.  Now,  assuming  that  a  rafter  with 
a  breadth  of  8  in.  will  meet  the  requirements,  we  must  find 
the  requisite  area  of  the  rafter  by  the  method  given  in  Art. 
1 808. .  The  total  length  of  the  rafter  measured  along  its  cen- 
ter line  is  16  ft.  6  in. ;  hence,  the  length  of  one  pillar  is  one- 
half  of  the  total  length  of  the  rafter,  or  8  ft.  3  in. ,  equal  to  99  in. 

Applying  formula  128,  given  in  Art.  1808,  we  have 
Breaking  load  per  square  inch  of  area  of  pillar  = 
5,000  5,000       ..  .^.  ,. 

1  +  (^  X  .OOl) 


RAILROAD    STRUCTURES.  12G5 

With  a  factor  of   safety  of   8,  this  rafter  will  bear  per 

square  inch  of  area,  -^— —  =  388  lb. 

8 

The  stress  g  I  upon  this  rafter  is  27,300  lb.,  and  to  safely 
resist  the  stress  it  will  require  a  rafter  whose  cross-sectional 

area  is     J    —  =  70  sq.  in.     As  we  have  assumed  a  breadth 
o88 

70 
of  8  in.,  the  depth  will  be  —  =  8.75  in. 

8 

The  rafter  must  be  notched  on  the  under  side  to  receive 
the  cast-iron  socket  for  the  stiffener ;  consequently,  it  will  be 
best  to  make  the  depth  10  inches,  a  size  that  is  readily 
obtained  in  the  market. 

In  the  parallelogram  g  I  h  k,  the  diagonal  k  I  represents 

the  pull   along  the  tie  beam.      Half  of  this  stress  ;//  /  is  in 

one  direction  from  the  foot  of  the  king-rod,  and  half    in   k 

in  the  other  direction,  making  a  uniform  stress  of  in  I  = 

23,500  lb.  throughout  the  tie-beam.     The  effect  of  this  pull 

is  to  shear  off  the  end  of  the  tie-beam  against  which  the 

rafter  abuts.     By  reference  to  Art.  1  809,  we  find  the  safe 

shearing  stress  along  the  grain  for  yellow  pine  is  400  lb.  per 

sq.  in.,  and  to  resist  a  stress  of  23,500  lb.  it  will  require 

.23  500 
'  *  ^     =  59  sq.  in.,  nearly.     The  distance  from  the  foot  of 
400 

the  rafter  to  the  end  of  the  tie-beam  is  12  in.      Assuming  a 

breadth  of  8  in.  for  the  stringer,  we  will  have  to  oppose  the 

given  stress  of  23,500  lb.,  an  area  of   12  X  8  =  90  in.,  or 

nearly  double  the  required  area. 

The  stiffeners  a  b  and  c  </ support  only  half  the  weight  of 
the  rafter,  and  serve  only  to  keep  the  rafter  from  bending 
under  its  longitudinal  stress.  If  proportioned  for  their 
actual  loads,  they  would  appear  weak  and  out  of  proportion. 
We  accordingly  make  them  4  in.  X  8  in. 

The  size  of  the  king-rod  we  determine  as  follows:  The 
load  which  it  must  sustain  we  have  determined  to  be 
28,000  lb.  With  a  factor  of  safety  of  G,  its  ultimate,  or 
breaking,  load  will  be  28,000  X  G  =  1G8,000  lb.  By  refer- 
ence to  Table  53,  Art.    1813,  we  find  the  diameter  of  a 


1266  RAILROAD   STRUCTURES. 

bolt  with  a  breaking  stress  of  108,000  lb.  is  nearly  2:^  in. 
We  accordingly  specify  a  2i-in.  king-rod. 

The  king-rod  passes  through  both  tie-beam  and  needle- 
beam,  being  fitted  at  both  head  and  nut  with  large  cast 
washers. 

As  all  floor-beams  rest  upon  the  needle-beam,  it  must 
therefore  carry  half  the  weight  of  the  floor  and  its  load,  i.  e., 
it  must  carry  all  the  load  between  the  points  j,  y.  This  we 
have  already  found  to  be  4,000  X  14  =  50,000  lb.,  a  uni- 
formly distributed  load  which  is  equivalent  to  a  center  load 

of  5^i^  =  28,000  lb.     The  length  of  the  needle-beam  from 

center  to  center  of  king-rods  is  18  ft.  8  in.  A  beam  of  this 
length  and  capable  of  bearing  a  center  load  of  28,000  lb. 
would  be  unwieldy.  We  accordingly  truss  the  needle-beam 
by  putting  in  a  vertical  strut  q  of  cast  iron  at  the  center 
of  the  beam,  and  throw  the  stress  upon  the  ends  of  the 
tie-beam  by  means  of  the  rods  r,  r,  thus  converting  a 
transverse  center  load  into  a  /////.  By  this  means  we  re- 
duce the  theoretical  span  of  the  needle-beam  to  one-half 
of  its  actual  length.  This  truss  is  the  reverse  of  the 
one  just  described,  the  strut  q  in  the  truss  P  s  p  (see 
section  C)  taking  the  place  of  the  king-rod  e  f  \x\.  the 
truss  n  e  o. 

The  strut  q  supports  one-half  the  load  carried  by  the 
needle-beam,  that  is,  all  that  part  of  its  load  between  the 
two  points  X,  X,  and  practically  divides  the  needle-beam  into 
two  spans,  each  equal  to  one-half  its  lengrti  from  center  to 
center  of  the  king-rods,  or  9  ft.  4  in.  long.  Each  of  these 
beams  will  support  one-half  of  the  total  load  of  the  needle- 
beam,  or  28,000  lb.,  which  is  a  uniformly  distributed  load, 

and   equivalent    to   a   center    load    of  , — ^— —  =  14,000   lb. 

With  a  factor  of  safety  of  0,  the  center  cross  breaking  load 
will  be  14,000  X  6  =  84,000  lb.  Assuming  a  breadth  of 
12  in.  for  the  needle-beam,  we  determine  its  depth  by 
Art.  1807.  The  constant  for  center  breaking  loads  for 
long-leaf  yellow  pine  is  550  (Art.  1802). 


RAILROAD   STRUCTURES.  1267 

Substituting  the  known  values  in  formula  127, 

breadth       square  of  depth 

,       ,  .       J     J      in  inches  in  incites  ^ 

center  breaki7ig  load  =  — -. , — -, r—^ X  C. 

length  of  span  tn  feet 

and  denoting  the  required  depth  by  x,  we  have 
84,000  =  ^-1^X550; 

,  -      783,720      -,  ,o  w 

whence,  ^.  =  ___  =  „8. 75, 

and  X—  10.9  in.,  nearly, 

the  required  depth  in  inches  of  the  needle-beam. 

Making  the  length  of  the  strut  2  ft.  6  in.,  we  draw  lines 
p  s,  p  s  to  denote  the  straining  rods  r,  r  of  the  truss.  Lay- 
ing off  from  s  upwards,  to  a  scale  of  20,000  lb.  to  the  inch, 
the  distance  s  t  =  14,000  lb.,  the  center  load,  we  complete 
the  parallelogram  s  u  t  v.  The  sides  s  «,  s  v  represent  the 
stress  in  the  straining  rods  r,  r.  By  the  given  scale  these 
sides  measure  23,000  lb.  This  stress  we  divide  between  the 
two  rods  w,  shown  in  section  in  the  detail  at  A.     The  stress 

upon  each  rod    is,   therefore,  -^- —  =  11,500  lb.     With  a 

factor  of  safety  of  6,  the  breaking  stress  would  be  11,500  X 

6  =  09,000   lb.     We    accordingly  look  in   Table  53  for  the 

diameter  of  a  rod  with  a  breaking  stress  of  69,000  lb.,  and 

find  it  to  be  lyV  in.     To  insure  ample  safety,  we  increase 

the  diameter  to  1^  in.     The  pull  placed  upon  the  rods  r,  r 

places  the  needle-beam//  under  compression  to  an  amount 

equal  to  u  y,  which,  by  the  given  scale,  amounts  to  21,500  lb. 

We    find    by   reference    to    Art.    1809,   that    for   endwise 

crushing  stress  we  may  use  a  working  stress  of  3,000  lb.  per 

sq.  in.     Hencej  to  resist  this  stress  of  21,500  lb.,  we  must 

21  500 
add  to  the  area  of  the  needle-beam    ., '    .^   =7.17  sq.  in., 

nearly.  To  hold  the  strut  q  in  place,  ribs  cast  with  the  strut 
fit  into  notches  cut  into  the  under  side  of  the  needle-beam. 
These  notches,  as  well  as  those  cut  in  the  side  of  the  needle- 
beam  for  the  straining  rods,  somewhat  reduce  the  area  of 


1268 


RAILROAD   STRUCTURES. 


RAILROAD    STRUCTURES.  12G9 

its  cross-section,  and  to  insure  ample  strength  we  increase 
the  depth  of  the  needle-beam  to  12  in. 

The  straining  rods  are  fitted  at  both  ends  with  nuts  and 
heavy  cast  washers  which  cover  the  entire  end  of  the  needle- 
beam,  as  shown  in  the  cross-section  C,  and  in  detail  at  B. 
Ribs  are  cast  on  the  backs -of  the  washers,  which  fit  into 
grooves  cut  into  the  ends  of  the  needle-beam. 

The  floor  system  is  so  arranged  that  the  street  cars  shall 
use  only  one  side  of  the  bridge,  leaving  the  other  side  ex- 
clusively for  vehicles.  The  rails  are  laid  directly  over 
stringers,  which  are  proportioned  to  carry  cars  loaded  to 
their  utmost  capacity. 

A  fully  loaded  street  car  weighs  10  tons.  This  is  carried 
on  a  wheel  base  (the  horizontal  distance  between  the  cen- 
ters of  wheels)  of  6  ft.  6  in.  Say  this  is  equivalent  to  a 
center  load  of  7  tons,  or  3^  tons  on  each  stringer.  The 
depth  of  these  stringers  will,  of  course,  be  the  same  as  that 
of  the  floor-beams,  viz.,  12  in.  Their  breadth  we  find  by 
Art.  1806.  A  safe  center  load  of  3^  tons,  with  a  factor 
of  safety  of  7,  would    be  equivalent   to   a  breaking  center 

1     A    (^Ax.  .nAAAiK    49,000X14      686,000      ^^. 

loadof2Htons,  or 49,0001b.   -^^r^^^-  =  -j^^^  =  8.6m., 

the  required  breadth  of  track  stringers.  The  factor  of 
safety  being  large,  and  as  a  part  of  the  load  is  distributed 
among  adjacent  floor-beams,  we  may  safely  specify  for  these 
stringers  a  breadth  of  8  in. 

1814.  Queen-Rod  Truss. — The  form  of  truss  shown 
in  Fig.  631  is  called  a  queen-rod  truss,  or,  more  briefly, 
a  queen  truss.  The  essential  features  of  this  truss,  and 
those  which  distinguish  it  from  the  king-rod  truss  already 
described,  are  the  two  queen-rods  k^  I  and  the  strain- 
ing beam  gh.  The  remaining  parts,  viz.,  the  tie-beam  a  b, 
the  rafters  c  d  and  c  f,  and  the  needle  beams  ;«  and  «,  are 
similar  to  those  found  in  the  king-rod  truss,  or  king  truss. 

This  form  of  truss  is  frequently  used  for  short  spans,  on 
new  railroad  work,  especially  if  timber  is  abundant  and 
economy  in  cost  a  first  consideration. 


1270  RAILROAD    STRUCTURES. 

The  height  of  the  truss  should  be  such  that  the  slope  of 
the  rafters  will  be  approximately  45°,  which  is  the  angle  at 
which  a  brace  exerts  its  greatest  strength.  The  queen-rods 
should  divide  the  clear  span  (the  space  between  the  abut- 
ments) into  three  equal  parts. 

In  Fig.  631  the  span  is  36  ft.  in  length,  the  height  of  the 
truss  above  the  tie-beam  is  11  ft.,  and  the  queen-rods  divide 
the  span  into  three  equal  parts  of  12  ft.  each.  The  points 
y  and  z  are  midway  between  the  abutments  and  the  queen- 
rods,  and  the  point  x  is  midway  between  the  queen-rods. 
The  queen-rod  k  supports  its  own  weight  and  that  part  of 
the  truss  included  between  the  points  x  and  j^,  together  with 
its  load ;  the  queen-rod  /  supports  its  own  weight,  together 
with  that  part  of  the  truss  included  between  the  points 
X  and  z  and  its  load.  The  parts  of  the  truss  between  the 
abutments  and  the  points  y  and  z  are  supported  by  the 
abutments. 

The  truss  shown  in  Fig.  631  is  designed  for  a  railway  of 
standard  gauge,  and  for  an  equivalent  dead  and  live  load  of 
6,000  lb.  per  lineal  foot   of  span.     The   load  for  each  truss 

per    lineal   foot  will,   therefore,   be  -^-- —  =  3,000  lb.      The 

2 

distance  x  z  is  12  ft.     The  load   upon  the  queen-rod  /  will, 

therefore,  be  3,000  X  12  =  36,000  lb.,  and  with  a  factor  of 

safety    of    6,    the    ultimate    or     breaking    stress    will    be 

36,000  X  6  =  216,000  lb.,  which,  from  Table  53,  we  find  is 

the  breaking  stress  for  a  rod  of  2f  in.  diameter. 

We  accordingly  lay  off  from  o,  on  the  center  line  of  the 

queen-^od,  to  a  scale  of  20,000  lb.  to  the  inch,  the  distance 

<?/,  equal  to  36,000  lb.   We  then  complete  the  parallelogram 

0  r p  q^  and   find   that  the  stress  of  36,000  lb.,   which    the 

queen-rod  /  sustains,  passes  to  the  head  o  of  the  rod,  where 

it  is  converted  into  two  longitudinal  stresses,  one  of  which 

o  q   travels  down  the  rafter  c  d,  and  is  taken  up  by  the 

abutment  /:,  while   the  other   o  r   moves  in  the  direction 

o  r.     An  equal  stress  is  placed  upon  the  straining  beam  by 

the  load  carried  by  the  queen-rod  k.     This  stress  moves  in 

the  direction  g  h.     These  two  stresses  reacting  upon  each 


RAILROAD   STRUCTURES.  1271 

other  produce  a  stress  throughout  the  straining  beam  equal 
to  one  of  them.  This  stress  o  r,  we  find  by  the  given  scale 
of  forces,  amounts  to  42,800  lb.  The  stress  oq^  by  the  same 
scale,  amounts  to  56,000  lb.  The  rafter  c  </,  in  resisting  this 
stress,  acts  as  a  pillar.  In  determining  the  dimensions  of 
this  rafter,  we  will  assume  a  certain  breadth,  say  12  in.,  and 
then  find  the  depth  necessary  to  sustain  the  given  load,  the 
variety  of  timber  used  being  yellow  pine.  The  length  of 
the  rafter  is  16  ft.  4  in.=  196  in. 

From  formula  128,  Art.  1808,  we  have 

Breaking  load  per  square  inch  of  area  of  pillar  = 

5,000 

/  square  of  length  in  inches  \ 
\square  of  breadth  in  inches  ) 

Substituting  given  values,  we  have 
Breaking  load  per  square  inch  of  area  of  pillar  = 
5,000  5,000 


i  +  (^x.oo.)--^ 


=  2,415  lb. 


With  a  factor  of  safety  of  6,  the  working  stress  will  be 

2  415 

'  '  .      =  402  lb.   per  sq.   in.,   and  to  resist  the  given  stress 

of  56,000  lb.,  it  will  require  a  cross-sectional  area  of  — ^,— -  = 

402 

139  sq.  in.     As  the  assumed  breadth  of  the  rafter  is  12  in., 

139 
the  depth  will  be  --—  =  11.58  in.,  or,  using  the  next  larger 
1* 

size  in  even  inches,  we  have  12  in.  x  12  in.  for  the  size  of 
the  rafter. 

The  stress  upon  the  straining  beam  ^  h  is  42,800  lb.,  and 
its  length,  as  measured  on  the  center  line  of  the  beam,  is  12  ft. 
6  in.  It  will  be  at  once  apparent  that  with  less  stress  and 
with  less  length  than  the  rafter  e  d,  the  straining  beam  may 
be  of  smaller  size  and  yet  have  the  same  factor  of  safety. 
It  i  >  customary,  however,  to  make  both  rafter  and  straining 
beam  of  one  size,  as  they  form  a  better  joint  at  the  queen- 
rods   and   give   an   impression    of   greater   strength.     The 


1272  RAILROAD    STRUCTURES. 

needle-beams'  in  and  »  serve  only  as  ties  to  hold  the  trusses 
in  position.  The  cross-ties  are  laid  directly  upon  the  tie- 
beams,  16  in.  from  center  to  center.  At  0,000  lb.  per  lineai 
foot,  the  uniformly  distributed  load  upon  each  cross-tie  is 
G,000  X  1.333  =  7,998,  say  8,000  lb.,  which  is  equivalent  to  a 
center  load  of  4,000  lb.  With  a  factor  of  safety  of  G,  the  center 
breaking  load  will  be  4,000  X  6  =  24,000  lb.  The  distance 
between  tie-beams  is  12  ft.  10  in.,  say  13  ft.  Assuming  a 
breadth  of  8  in.  for  the  cross-ties,  and  denoting  the  required 
depth  by  -r,  we  find  the  depth  by  applying  the  rule  given  in 
Art.  1807,  as  follows: 

24,000  =  ^^5^  X  550, 
Jo 

whence,  ;r''  =  70.90, 

and  .r  =  8.4  in. 

As  we  notch  down  the  ties  1  in.  on  the  tie-beams,  we 
increase  this  depth  to  9  in. 

The  queen-rods  virtually  divide  the  bridge  span  into  three 
short  spans  of  12  feet  each.  We  accordingly  find  the 
dimensions  of  the  tie-beams  for  spans  of  that  length.  The 
load  upon  each  tie-beam  we  assume  at  3,000  pounds  per 
lineal  foot.  The  total  uniformly  distributed  load  on  the  tie- 
beam  is,  therefore,  3,000  X  12=  36,000  lb.,  which  is  equiva- 

or*    AAA 

lent  to  a  center  load  of  — '- —  =  18,000  lb.     With  a  factor  of 

z 

safety  of  6,  we  have  a  breaking  center  load  of  18,000  X  6  = 

108,000  lb. 

Assuming  a  breadth  of  12  inches  for  the  tie-beam,  we  find 

the  depth  by  the  rule  given  in  Art.  1 807.     Denoting  the 

required  depth  in  inches  by  ,r,  we  have 

108,000  =:^^^^^^ —  X  550; 

550-r'  =  108,000, 
whence,         ;f'  =  196.36 
and  X  =  14  in.,  the  required  depth  of  the  tie-beam. 

Besides  the  transverse  stress  upon  the  tie-beam,  there  is  a 


RAILROAD    STRUCTURES.  1273 

longitudinal  pull  /  q^  which  amounts  to  42,800  pounds. 
Allowing  a  working  stress   in  tension  of  3,000  pounds  per 

square  inch,  it  will  require      '         =  14.2G  square  inches  of 

3,000 

area  to  resist  this  pull.     We  add  this  area  to  that  already 

obtained  for  the  tie-beam,  being  careful  to  make  the  increase 

in  one  dimension  only,  viz.,  the  breadth.     This  gives  us  for 

the   final    dimensions    of   the   tie-beam    a    breadth    of    say 

13  inches  and  a  depth  of  14  inches. 

The  longitudinal  stress  in  the  rafter  c  d  develops  a  shear- 
ing stress  along  the  grain  at  the  foot  of  the  rafter  equal  to 
the  pull  in  the  tie-beam,  or  42,800  pounds. 

Allowing  a  working  stress  for  shear  along  the  grain  of 

42  800 
400  lb.  per  sq.  in.,  it  will  require— j——  ■=  107  sq.  in.  to  resist 

this  stress.  The  distance  from  the  foot  of  the  rafter  to  the 
end  of  the  tie-beam  is  12  in. ;  hence,  the  superficial  area 
opposed  to  this  shearing  stress  is  13  X  12=156  sq.  in., 
which  insures  ample  safety.  The  feet  of  the  rafters  are 
bolted  to  the  tie-beams,  thus  preventing  any  lateral  move- 
ment. 

The  needle-beams  /;/  and  n  serve  two  purposes,  viz.,  as 
ties  to  hold  the  tie-beams  in  position,  and  as  supports  for 
the  braces  j,  s  which  maintain  the  trusses  in  an  upright 
position.  These  braces  are  fastened  in  place  with  boat 
spikes.  The  trusses  are  further  braced  by  three  sets  of  X 
braces  /,  ^,  as  shown  in  the  cross-section  B.  Each  set  has  a 
length  equal  to  one-third  of  the  span.  The  ends  of  the 
braces  are  spiked  to  the  tie-beams  and  bolted  together  at 
the  point  where  they  cross  each  other.  On  the  inside  of 
each  tie-beam,  directly  over  the  bridge  seat,  a  groove  is  cut 
1  in.  in  depth  and  4  in.  in  breadth,  to  receive  the  spreader 
«,  as  shown  in  the  detail.  These  spreaders  are  4  in.  x  12  in., 
and  are  held  in  place  by  the  tie  bolts  v,  v,  which  are  1  in.  in 
diameter  and  fitted  with  cast  washers.  The  effect  of 
the  rails  is  to  distribute  the  loads  concentrated  upon  the 
driving  wheels  of  the  locomotive  over  the  entire  wheel  base, 
so  that  cross-ties  which  individually  could  not  sustain  these 


1274  RAILROAD   STRUCTURES. 

concentrated  loads  are  yet  amply  strong  enough  for  their 
share  of  the  distributed  load.  The  trusses  do  not  rest 
directly  upon  the  bridge  seats,  but  upon  two  G  in.  X  9  in. 
oak  timbers  iv,  w,  which  extend  the  full  length  of  the 
bridge  seat  and  distribute  the  weight  of  the  bridge  over  the 
entire  foundation. 

The  cast-iron  shoulder  block  at  head  of  rafters  is  shown 
in  detail  at  D.  The  bridge  seats  are  2  ft.  in  breadth,  and 
the  abutments  3  ft.  in  thickness  at  the  bridge  seat.  The 
faces  of  the  abutments  are  vertical,  while  their  backs  have 
a  batter  of  1^  inches  to  the  foot. 


WATER     STATIONS. 

1815.  Water  stations  are  points  along  a  railroad 
where  the  engines  stop  to  take  in  water.  Their  distance 
apart  will  depend  mainly  upon  the  amount  of  the  traffic, 
but  somewhat  upon  the  grades.  On  roads  with  a  light 
traffic,  water  stations  at  intervals  of  15  miles  will  meet 
every  requirement,  while  roads  with  a  heavy  traffic  and 
frequent  trains  may  require  them  at  every  5  or  6  miles. 

They  usually  consist  of  large  wooden  tubs  placed  upon  a 
strong  framework,  supported  by  heavy  pillars  which  rest 
upon  a  foundation  of  masonry.  The  tubs  are  generally 
circular  in  form,  the  bottom  diameter  being  a  few  inches 
larger  than  that  of  the  top  diameter,  in  order  that  the  iron 
hoops  may  drive  tight.  White  pine,  cedar,  and  redwood 
are  the  varieties  of  timber  principally  used  in  the  manufac- 
ture of  tanks.  The  staves  are  planed  by  machinery  speci- 
ally designed  to  give  them  the  proper  bevel,  so  that  when 
set  up  the  joints  are  close  and  water-tight.  The  staves  are 
fastened  together  at  the  top  with  a  single  dowel  between 
each  two,  merely  to  hold  them  in  place  while  being  set  up. 
The  pieces  forming  the  bottom  of  the  tank  are  doweled 
together  and  fit  into  a  groove  about  1  inch  in  depth, 
which  is  cut  into  the  staves  to  receive  them.  The  hoops 
are  fastened  together  with  lugs  which  grip  the  two  ends  of 
the  hoop.     The  two  lugs  are  united  by  a  bolt   threaded  at 


RAILROAD    STRUCTURES.  1276 

both  ends  and  fitted  with  nuts.  By  screwing  up  these  nuts, 
a  strain  is  put  upon  the  hoop.  The  hoops  are  first  nearly 
driven  to  place;  the  lugs  are  then  tightened  with  a  wrench, 
after  which  the  driving  is  finished. 

Railroad  water  tanks  hold  from  20,000  to  40,000  gallons. 
A  common  size  is  16  ft.  in  diameter  and  IG  ft.  in  height, 
holding  about  21,000  gallons.  All  tanks  holding  above  200 
barrels  are  made  from  3-in.  stuff.  This  thickness  is  some- 
what reduced  by  planing.  The  bottom  of  the  tank  should  be 
from  10  to  12  ft.  above  the  tops  of  the  rails.  It  is  a  com- 
mon practice  to  enclose  the  tank  in  a  framed  structure,  the 
foundation  and  post  supports  forming  the  first  story,  and 
the  tank,  together  with  its  covering,  the  second  story. 
Where  the  supply  of  water  is  pumped,  the  first  story  is  often 
used  as  a  pump  house,  and  a  fire  is  usually  maintained  in 
winter  to  prevent  the  freezing  of  the  water.  At  division  or 
terminal  points,  where  many  engines  are  to  be  supplied,  the 
tank  is  made  proportionately  larger,  and  often  two  are 
placed  together. 

It  is  desirable  to  combine  a  coaling  with  a  water  station, 
in  order  that  an  engine  may  take  both  fuel  and  water  at  the 
same  time.  Such  an  arrangement  is  usually  made  at  divi- 
sion points  and  terminals,  though  it  is  not  always  practi- 
cable to  place  a  water  tank  and  coaling  station  side  by  side. 

A  tender  of  coal  will  serve  for  several  tankfuls  of  water, 
so  that  coaling  stations  situated  at  division  points,  at  inter- 
vals of  say  100  miles,  will  serve  every  requirement. 

When  the  railroad  has  a  double  track,  it  is  customary  to 
place  a  water  tank  on  each  side  of  the  roadway,  so  that 
engines  may  take  water  from  either  track. 

The  tank  house  should  stand  near  the  track,  leaving  only 
from  2  to  4  feet  clearance  for  cars. 

1816.  Source  of  Water  Supply. — The  least  expen- 
sive and  most  satisfactory  water  supply  is  that  obtained 
from  either  springs  or  brooks  which  have  sufficient  elevation 
to  deliver  water  into  the  tank  by  gravity  and  so  avoid  the 
expense  of  pumping.     Clear,  pure  water,  as  free  as  possible 


137r)  RAILROAD    STRUCTURES. 

from  mineral  matter  in  solution,  is  greatly  to  be  desired.  If 
the  stream  from  which  the  supply  is  obtained  is  liable  to  be- 
come muddy  from  freshets,  a  reservoir  of  suitable  size  should 
be  constructed  and  kept  constantly  full  of  clear  water,  so 
that,  in  case  of  a  freshet,  the  flow  of  the  water  into  the 
reservoir  may  be  stopped  until  the  stream  runs  clear. 

Where  spring  water  is  used,  and  the  supply  in  times  of 
drouth  is  liable  to  run  short,  a  reservoir  of  ample  capacity 
should  be  constructed,  and  the  surplus  water  stored  for 
future  use. 

When  the  source  of  supply  is  too  low  to  be  delivered  by 
force  of  gravity,  resort  is  had  to  pumping.  Formerly,  horse- 
power was  used  to  a  considerable  extent  for  pumping,  but  of 
late  years  steam  and  wind  power  have  been  exclusively  em- 
ployed. Pumping  by  wind  mills  is  the  least  expensive,  and, 
but  for  occasional  calms,  the  most  satisfactory.  The  only 
way  to  provide  against  a  short  supply  due  to  calms  is  to  make 
the  capacity  of  the  water  tanks  adequate  for  a  number  of 
days'  supply.  The  tank  has  three  pipes  :  an  inlet  pipe  by 
which  the  water  enters  the  tank,  a  waste  pipe  for  prevent- 
ing overflow,  and  a  discharge,  or  feed-pipe,  7  or  8  inches  in 
diameter,  in  or  near  the  bottom,  through  which  the  water 
flows  to  the  tender  tank.  The  discharge  pipe  is  from  8  to  10 
feet  long,  and  jointed  at  the  end  which  joins  the  tank,  so 
that  when  the  tender  tank  is  filled,  the  discharge  pipe,  acted 
upon  by  a  counterweight,  swings  either  sideways  or  verti- 
cally on  its  hinge  joint,  out  of  reach  of  the  cars.  The  dis- 
charge pipe  at  its  connection  with  the  tank  is  provided  with 
a  valve  which  has  a  lifting  gate.  Movement  is  communica- 
ted to  this  gate  by  means  of  a  lever,  the  short  arm  of  which 
is  attached  to  the  valve  rod.  The  long  arm  of  the  lever  has 
a  rope  attached,  which  hangs  within  reach  of  the  engineman. 

When  taking  water,  the  discharge  pipe  is  lowered  and 
swung  over  the  water  hole  in  the  tender  tank.  The  engine- 
man  then  pulls  down  on  the  lever.  This  action  raises  the 
valve  stem  and  allows  the  water  to  flow  from  the  water  tank 
into  the  tender  tank.  Tender  tanks  hold  from  2,500  to  3,500 
gallons. 


RAILROAD   STRUCTURES. 


1277 


1278  RAILROAD    STRUCTURES. 

1817.  Standard  Water  Titnks. — A  general  plan  of 
a  standard  water  tank  is  given  in  Fig.  ('/.VZ.  The  foundation 
is  shown  in  plan  at  A;  a  plan  of  the  arrangement  of  timbers 
composing  the  tank  seat  or  deck  is  shown  at  /j,  and  a  com- 
plete elevation  of  the  tank  at  C.  The  foundations  should  be 
of  the  most  substantial  character,  of  well-dressed  stone 
laid  in  cement  mortar.  The  foundation  consists  of  either 
continuous  walls  laid  at  right  angles,  upon  which  the  sills 
are  placed  and  the  posts  mortised  into  them,  or  a  pediment 
of  pyramidal  form  is  built  for  each  post,  as  shown  in  the 
figure.  Each  ppst  is  secured  to  its  pediment  by  a  dowel  1  in. 
in  diameter  by  6  in.  in  length.  The  stone  pediment  forms  a 
very  substantial  foundation.  It  is  effective  in  appearance 
and  does  away  with  the  sills,  which  are  apt  to  decay  from 
alternate  wetting  and  drying. 

The  posts  are  connected  together  by  girts  a,  d,  c,  which 
are  tenoned  into  the  posts  and  fastened  with  treenails.  This 
connection  is  further  strengthened  by  |  in.  tie-rods  d,  e,/, 
which  pass  through  each  row  of  posts,  a  cast  washer  being 
placed  under  the  head  and  nut  of  each  tie-rod.  Between  each 
two  rows  of  girts  a  series  of  X  braces  ^,  //,  k  is  placed  and 
securely  spiked  to  the  posts  and  girts.  The  caps  /,  w,  n,  o, 
upon  which  the  beams  which  compose  the  deck  rest,  are 
12  in.  X  12  in.,  and  fastened  to  the  posts  by  mortise  and 
tenon.  The  deck  is  composed  of  two  sets  of  timbers  laid  at 
right  angles  to  each  other.  The  first  set,  laid  directly  upon 
the  posts,  are  3  in.  X  12  in.,  and  uniformly  spaced.  They  are 
held  together  and  strengthened  by  bridging  (see  detail  /?) 
besides  being  spiked  to  the  caps.  The  second  set  of  deck 
timbers  are  4  in.  X  6  in.,  and  laid  at  right  angles  to  the  floor- 
beams.  They  are  spaced  19  in.  center  to  center,  and  ex- 
tend to  within  3  in.  of  th6  tank  staves.  They  are  in  direct 
contact  with  the  bottom  of  the  tank,  and  receive  the  entire 
weight  of  the  water  contained  in  the  tank  without  allowing 
any  of  its  weight  to  rest  upon  the  staves.  The  deck  is  usually 
made  octagonal  in  form,  and  where  the  tank  is  not  covered 
by  a  house,  the  deck  is  made  to  project  far  enough  from  the 
tank  (as  shown  at  .£^)  to  protect  the  foundation  and  timber 


RAILROAD   STRUCTURES. 


1279 


supports  from  the  weather.  The  sides  of  the  tank  flare  or 
batter  outwards  at  the  rate  of  ^  in.  to  the  foot,  so  that  the 
hoops  will  drive  tight. 

The  discharge  pipe/,  when  not  in  use,  takes  the  position 
shown  in  the  figure,  being  held  in  that  position  by  the 
weighted  ball  ^,  which  is  attached  to  the  chain  r,  running 
through  the  sheave  s,  and  thence  to  its  connection  with  the 
discharge  pipe.  A  cross-section  of  the  track  is  shown  at  G, 
the  top  of  the  rail  being  12  ft.  below  the  outlet  of  the 
discharge  pipe. 

The  valve  connection  of  the  discharge  pipe  with  the  tank 
is  shown  in  Fig.  633.     The  connection  may  be  made  either 


Fig.  6.3.3. 

through  the  side  or  bottom  of  the  tank.  The  bottom  valve 
connection  is  shown  in  the  figure.  The  valve  rod  a  is 
attached  to  the  short  arm  of  the  lever  d.  The  weight  f , 
attached  to  the  end  of  the  short  arm  of  the  lever,  holds  the 
valve  firmly  in  place.  A  rope  is  attached  to  the  end  d  of  the 
long  arm  of  the  lever  and  hangs  within  reach  of  the  engine- 
man.  By  pulling  down  on  this  rope,  the  valve  is  raised, 
and  the  water  flows  through  the  discharge  pipe  e  to  the 
tender  tank.     The  vacuum  pipe  /  admits  air  to  the  discharge 


1280 


RAILROAD   STRUCTURES. 


pipe  after  the  valve  comes  to  its  seat,  so  that  the  discharge 
pipe  is  quickly  voided. 

1818.     Water  Columns. — Where  space  is  limited  and 
the  head  of  water  is  sufficient,  a  water  column    (see    Fig. 

034)  is  used  in  place  of 
/  W==^^'**ni  a  tank.    One  advantage 

of  a  water  column  is  in 
its  economy  of  space, 
as  will  be  at  once  ap- 
parent. It  can  safely 
be  placed  between  the 
parallel  tracks  of  a 
double-track  road,  and 
serve  engines  on  both 
tracks  equally  well. 

This  water  column 
consists  of  a  globe 
valve  a,  connecting  with 
the  main  water  pipe  b^ 
and  enclosed  in  acham- 
FiG.  634.  ber  of   brick   masonry. 

This  chamber  is  covered  with  a  substantial  floor  of  timber,  and 
forms  the  foundation  for  the  pedestal  c,  which  supports  the 
crane-shaped  water 
column  d.  This 
column  is  jointed 
at  its  connection 
with  the  pedestal,  so 
that  the  discharge 
pipe  may  be  readily 
swung  over  the  ten- 
der when  taking 
water.  The  cast- 
iron  globe  f  (Fig. 
035)     is    connected 

with  the  valve  disk  Fig.  ess. 

by  means  of  the  valve  rod  g^  and   by  its  weight  keeps  the 


RAILROAD   STRUCTURES.  1281 

valve  closed.  When  taking  water,  the  lever  h  is  de- 
pressed. This  causes  the  short  arm  k  of  the  lever  to 
rise,  and  lifts  the  globe/".  The  weight  being  thus  removed 
from  the  valve,  the  disk  is  lifted  by  the  pressure  of  the 
water  which  flows  through  the  discharge  pipe  to  the  tender 
tank. 

COALING    STATIONS. 

1819.  Coaling  stations  are  points  along  a  railroad 
where  fuel  is  kept  in  stock  for  supplying  locomotives.  They 
are  placed  at  all  division  points,  large  yards,  and  sometimes 
at  the  summits  of  long  grades  where  pushers  are  employed. 
Formerly,  many  roads  used  wood  as  fuel,  but  coal,  which  is 
far  more  lasting  and  more  economical  of  space,  is  now  almost 
universally  used.  The  coaling  stations  of  thirty  years  ago 
were  very  primitive  in  design.  The  fuel  was  loaded  by 
hand,  the  coal  being  loaded  into  small  carts  and  dumped 
from  a  platform  into  the  tender.  A  very  decided  advance 
in  design  was  made  when  the  coal  pockets  shown  in  Fig. 
636  were  introduced.  The  pockets  are  supported  on  bents 
of  trestlework,  each  pocket  comprising  the  space  between 
two  bents.  The  figure  shows  the  cross-section  at  A,  and 
the  side  elevation  at  B.  Each  bent  is  supported  by  four 
posts,  a,  b,  c,  and  d.  All  are  vertical  except  the  last,  d^ 
which  has  a  batter  of  3  in.  to  the  foot.  Timbers  e  f,  6  in.  x 
12  in.,  are  bolted  to  both  sides  of  the  posts  and  supported 
by  batter  posts ^,  h,  also  6  in.  x  12  in.,  which  are  bolted  to 
both  post  and  sill.  These  combined  form  the  support  to 
the  pocket  floor  system,  which  consists  of  6  in.  x  10  in. 
floor-beams  >^,  /,  etc.,  laid  2  ft.  center  to  center,  as  shown 
in  the  figure,  and  drift-bolted  to  the  supports.  Upon 
these  floor-beams  is  laid  a  flooring  of  3-in.  oak  planks, 
which  are  covered  with  plates  of  sheet  iron  from  ^  to 
y\  in.  in  thickness  to  protect  them  from  the  wear  of  the 
coal. 

The  bents  are  spaced  12  feet,  center  to  center,  and 
planked  on  both  sides  above  the  floor  with  3-in.  planks, 
forming  a  series  of  pockets.     This  provides  for  storing  coal 


1282 


RAILROAD    STRUCTURES. 


RAILROAD   STRUCTURES.  1283 

of  different  sizes,  so  as  to  meet  the  requirements  of  the  dif- 
ferent types  of  engines.  The  partition  walls  are  also  pro- 
tected with  sheet  iron.  The  track  stringers  are  placed 
directly  over  the  middle  posts.  They  consist  of  two  pieces 
8  in.  X  16  in.,  and  extend  over  two  bents,  as  in  ordinary 
trestle  building.  The  ties  are  7  in.  X  8  in.  X  10  ft.,  and 
notched  down  1  in.  on  the  stringers.  They  carry  an  8-in. 
X  8-in.  guard-rail,  which  is  also  notched  1  in.  on  the  ties. 
Stringers  are  fastened  to  cap  with  drift-bolts,  |  in.  x  24  in  , 
round  iron.  Stringers  are  spaced  3  in.,  and  held  in  place  by 
separators  of  cast  iron.  Stringer  bolts  are  fin.  X  22  in. 
The  bents  are  further  tied  together  by  the  timbers  ;//,  w, 
12  in.  X  12  in.,  which  are  fastened  to  the  caps  with  |-in. 
X  20-in.  drift-bolts,  and  by  the  timbers  «,  n.  Gin.  x  12  in., 
which  partly  support  the  plank  walks  o.  These  walks  are 
protected  by  a  railing  /  /,  which  is  supported  by  posts 
spiked  to  the  timbers  ///,  ;//. 

The  coal  is  conducted  from  the  pocket  to  tender  by  means 
of  the  spout  or  chute  r,  composed  of  planks  and  sheet  iron. 
This  chute,  when  in  position  for  coaling  a  tender,  is  repre- 
sented by  r,  and  when  not  in  use,  by  r' .  It  is  fitted  with 
counterweights  s,  somewhat  heavier  than  itself,  which  en- 
able the  engineman  to  handle  it  with  ease.  The  mouth  of 
the  pocket  is  closed  by  a  sliding  door  /,  of  cast  iron,  which 
works  in  guides,  and  is  operated  by  means  of  a  lever  ti. 
This  lever  is  attached  to  a  grooved  wheel,  in  which  works  a 
chain  which  is  attached  to  the  door  /.  The  lever  attach- 
ment is  shown  in  detail  at  C.  The  chain  is  fastened  to  the 
groove  of  the  wheel  with  a  staple  v.  Power  is  applied  to 
the  lever  by  means  of  the  rope  w.  The  wheel  is  supported 
by  two  4-in.  X  12-in.  oak  timbers  .r,  x,  which  are  bolted  to 
the  plate  y  and  the  timber  in.  These  are  so  fastened  at  the 
top  as  to  project  forward,  as  shown  at  x  in  the  elevation. 
This  throws  the  wheel  axis  forward,  so  that  the  lifting 
chain  will  clear  the  woodwork. 

To  take  coal,  the  engineman  first  lowers  the  spout  r\  he 
then  pulls  down  the  lever  u  by  means  of  the  rope  u\  which 
raises  the  door  /  and  allows  the  coal  to  run  from  the  pocket 


1284  RAILROAD   STRUCTURES. 

into  the  tender.     The  pocket  floor  at  z  should  not  be  less 
than  11  ft.  above  the  top  of  the  rail. 

The  loaded  cars  of  coal  are  dumped  directly  from  the 
track  above  into  the  pockets.  The  supply  track  is  usually 
an  incline  plane,  with  a  grade  as  sharp  as  is  consistent  with 
safe  operation.  Sometimes,  where  space  is  very  limited,  the 
loaded  cars  of  coal  are  hauled  to  the  top  of  the  pockets  by 
cable  over  a  steep  incline. 

1 820.  A  Modern  Coaling  Station. — A  modern  coal- 
ing station  is  shown  in  Fig.  037,  in  which  the  coal  is  han- 
dled by  machinery.  The  figure  includes  a  general  plan  of 
the  station,  the  elevation  being  shown  at  A  and  the  cross- 
section  at  B.  The  power  to  drive  the  machinery  is  fur- 
nished by  the  engine  c.  The  machinery  consists  of  an  ele- 
vator d  dzxiA  a.  conveyor  e  e,  composed  of  link  belts  carrying 
projecting  pieces  of  board,  which,  as  they  slide  through 
troughs  lined  with  sheet  iron,  form  elevating  or  conveying 
buckets,  first  elevating  the  coal  from  the  pocket  beneath  the 
track  where  it  is  dumped  from  the  car,  to  the  head  of  the 
incline,  and  then  conveying  it  to  the  different  pockets,  where 
it  is  stored  ready  for  the  use  of  locomotives.  The  link  belts 
are  driven  by  sprocket  wheels  7^  and  ^.  The  power  is  trans- 
mitted from  the  engine  to  the  machinery  by  means  of  a  wire 
rope  belt.  The  main  sheaves  /i  and  k  are  6  feet  in  diameter. 
They  are  attached  to  shafts  carrying  pinions  which  drive  the 
gears  /and  ;//,  and  with  them  the  sprocket  wheels y and  g: 
The  coal  to  be  elevated  to  the  coal  pockets  is  first  dumped 
from  the  car  ;/  into  a  chamber  beneath  the  track.  The  coal 
runs  by  gravity  from  this  chamber  through  the  opening  0 
into  the  elevating  chute  /,  which  is  lined  with  sheet  iron, 
and  as  the  projecting  boards  carried  by  the  link  belt  pass 
under  the  sprocket  wheel  g,  they  push  the  coal  before  them, 
forming  a  series  of  buckets,  which  carry  the  coal  to  the  point 
r,  where  an  opening  in  the  chute  allows  the  coal  to  fall  into 
the  conveying  chute  s.  Here  a  similar  series  of  buckets, 
passing  around  the  sprocket  wheel  /,  collects  the  coal  as  it 
falls  from  the  elevator  chute  and  carries  it  to  the  storage 


'/  ///  / .  ',/l/l,l/' 


'-////////////////////// 


*55m^^;mm#.^M;^^^i^Ml:^^^^^f^^, 


RAILROAD   STRUCTURES.  1285 

pockets  of  the  station.  In  the  bottom  of  the  conveying 
chute,  and  directly  above  each  pocket,  is  an  opening  of  suit- 
able dimensions.  These  openings  are  fitted  with  sliding 
covers,  which  are  close  fitting,  and  all  of  them  are  closed 
excepting  the  one  connecting  with  the  pocket  to  be  filled. 
The  sheave  ii  is  fitted  with  a  sliding  journal  which  provides 
for  taking  up  any  slack  in  the  wire  rope  drive  due  to  stretch- 
ing. The  link  belt  of  the  elevator  on  its  return  is  supported 
by  the  sheaves  v  and  w,  and  the  conveyor  belt  by  the  sheave 
X.  These  sheaves  are  supported  by  brackets  bolted  to  the 
floor  timbers  of  the  chutes.  The  pockets  are  enclosed  with 
planks  and  covered  by  a  slate  roof,  an  open  space  2  feet  in 
width  being  left  under  the  eaves  for  the  free  circulation  of 
air.  The  general  form  of  the  coal  pockets  is  the  same  as 
those  shown  in  Fig.  636.  The  coaling  spouts  j,  y  are  made 
of  cast  iron,  instead  of  plank  lined  with  sheet  iron.  The 
spouts  are  raised  and  lowered  by  means  of  counterweights^ 
as  shown  both  in  elevation  and  cross-section.  The  pockets 
are  lined  with  sheet  iron  or  steel.  The  gauge  line  of  the 
track  is  commonly  placed  5  ft.  from  the  face  of  the  coal 
pockets,  and  the  bottom  of  the  pockets  at  their  connection 
with  the  spouts  12  ft.  above  the  rail. 


TURNTABLES. 
1821.  A  turntable,  as  shown  in  Fig,  638,  is  a  platform 
usually  from  50  to  70  feet  long,  and  from  8  to  10  feet  wide, 
upon  which  a  locomotive  and  tender  may  be  run  and  then 
turned  horizontally  through  any  portion  of  a  circle,  and  thus 
be  transferred  from  one  track  to  another  forming  any  angle 
with  it.  The  table  is  supported  by  a  pivot  under  its  cen- 
ter, and  by  wheels  or  rollers  under  its  ends.  Beneath  the 
platform  is  excavated  a  circular  pit  4  or  5  feet  deep,  having 
its  circumference  lined  with  brick  or  stone  masonry  2  feet 
in  depth,  and  capped  with  either  cut  stone  or  wood.  The 
diameter  of  the  pit  in  the  clear  is  about  2  inches  greater 
than  the  length  of  the  turntable.  The  masonry  lining  is 
usually  built  with  a  step  (see  elevation  B),  which  supports 


1286 


RAILROAD    STRUCTURES. 


i2/. 


RAILROAD    STRUCTURES.  1287 

the  rail  upon  which  the  end  rollers  travel.  At  the  cen- 
ter of  the  pit  is  a  substantial  foundation  of  masonry, 
upon  which  the  pivot  rests.  This  foundation  should  be 
4  or  5  feet  in  depth  and  composed  of  large,  regularly 
shaped  stones  laid  in  cement  mortar  and  well  bonded  to- 
gether. This  foundation  is  capped  by  a  single  stone  6  ft. 
square  and  12  in.  in  thickness.  The  pivot,  shown  in  de- 
tail at  C,  is  fastened  to  the  foundation  by  heavy  anchor 
bolts  reaching  the  full  depth  of  the  masonry.  Sometimes 
the  pit  is  floored  over  with  plank,  but  this  so  greatly  in- 
creases the  weight  of  the  table,  besides  involving  the  ex- 
pense of  renewal,  that  it  should  be  dispensed  with  unless 
circumstances  make  a  floor  necessary.  Usually,  only  a 
walk  of  planks,  supported  by  the  projecting  ties,  is  al- 
lowed. 

The  turntable  should  be  somewhat  longer  than  the  total 
lengch  of  both  locomotive  and  tender,  so  as  to  permit  the 
engineman  to  move  his  engine  a  few  feet  in  either  direction 
from  the  pivot  in  order  to  secure  an  equilibrium.  With  a 
little  practice,  such  an  equilibrium  is  easily  obtained.  By 
this  means  the  friction  while  turning  is  confined  chiefly  to 
the  center  of  motion. 

Probably  the  best  turntables  in  use  in  America  are  manu- 
factured by  Wm.  Sellers  &  Co.,  of  Philadelphia,  Pa. 
The  turntable  shown  in  Fig.  638  is  a  copy  of  their  recent 
standard.  They  are  expensive  in  first  cost,  but  most 
economical  both  in  operation  and  in  the  matter  of  repairs. 
Being  composed  chiefly  of  metal  they  are  very  enduring, 
and  as  the  parts  are  readily  duplicated,  repairs  are  simple 
and  expeditious.  One  man  can  readily  turn  one  of  these 
tables,  loaded,  without  the  assistance  of  machinery.  They 
consist  of  two  heavy  cast-iron  girders,  perforated  by  circu- 
lar holes  to  reduce  weight  and  cost.  Each  girder  consists 
of  two  parts,  a  and  b,  fastened  to  a  heavy  central  boxing, 
shown  in  cross-section  at  C. 

The  girders  are  fastened  to  it  by  means  of  heavy  iron 
bars  c,  d,  3J  in.  square,  of  rolled  iron,  fitted  into  sunk 
recesses  on  top  of  the  boxing,  and  tightened  in  place  by 


1288  RAILROAD    STRUCTURES. 

means  of  wedges,  and  also  by  means  of  two  2:J:-in.  key  bolts 
at  the  base  of  the  girders,  passing  through  the  holes  r,  /, 
and  confined  by  the  keys^,  ^.  The  central  portion  of  the 
boxing  is  a  hollow  cone  ^,  open  at  top  and  bottom,  and  sur- 
rounding the  hollow  conical  pivot  post  I'.  The  pivot  shell 
is  about  If  in.  thick.  On  top  of  the  post  rests  a  heavy, 
loose,  cast-iron  cap  /,  which  permits  of  a  slight  rocking  motion 
of  the  entire  platform  as  the  engine  enters  and  leaves  the 
turntable.  This  cap  supports  the  steel  box  (see  detail  D) 
containing  the  friction  rollers  w.  There  are  fifteen 
of  them,  each  about  2f  in.,  both  in  length  and  greatest 
diameter.  They  have  no  axles,  but  lie  loosely  in  the  lower 
part  of  the  box,  filling  its  circumference,  save  a  half-inch  of 
space  left  for  the  free  movement  of  the  rollers.  In  the 
direction  of  their  axis  they  have  but  ^  in.  play  in  the  box. 
The  lid  «  of  the  box  rests  directly  upon  the  rollers  them- 
selves, and  does  not  come  down  to  the  lower  part  o  of  the 
box  by  ^  inch.  Both  the  rollers  and  the  box  enclosing  them 
are  finished  with  mathematical  accuracy,  so  as  to  ensure  a 
perfect  bearing  between  them.  The  rollers  are  kept  con- 
stantly oiled,  as  ease  in  turning  depends  entirely  upon  their 
being  well  lubricated.  On  top  of  the  rollers  is  the  cap/, 
which  is  secured  by  heavy  bolts.  This  cap  does  not  rest 
directly  upon  the  boxing,  but  is  separated  from  it  by  wooden 
wedges  g,  q,  by  means  of  which  the  table  may  be  raised  or 
lowered  and  its  height  exactly  adjusted  to  the  connecting 
track. 

When  the  engine  is  properly  balanced,  the  cap  bolts  sus- 
tain all  the  load  placed  upon  the  turntable,  excepting  the 
small  amount  carried  by  the  tracks  at  the  end  of  the 
platform. 

When  properly  balanced  on  a  Sellers'  turntable,  the  end 
wheels  should  only  just  touch  the  rails.  The  diameter 
of  the  roller  box  being  15  in.,  it  is  not  difficult  to  balance 
the  locomotive  and  tender.  All  turntables  should  be  pro- 
vided with  the  means  of  being  raised  -or  lowered,  and  so 
adjusted  as  to  give  the  proper  bearing  upon  the  circular 
track. 


0-2^^-2  -nopuijf 


$c-fn»tjtis  ptia 


1290  RAILROAD    STRUCTURES. 

SECTION   BUILDINGS. 

1822.  Tool  Houses. — At  the  headquarters  of  each 
section  a  tool  house  is  erected  for  the  storage  of  hand  and 
push  cars,  track  tools,  and  all  track  materials  which  may  be 
damaged  by  exposure  to  the  weather,  or,  on  account  of 
their  portability,  likely  to  be  stolen.  Among  the  latter 
class  are  track  bolts  and  track  spikes,  nails  and  cut  spikes, 
shim  and  pin  timber,  etc.  The  tool  house  should  not  con- 
nect directly  with  the  main  track,  but  with  a  siding,  so  that 
a  train  standing  on  the  main  track  will  not  interfere  with  a 
crew  starting  for  work  with  either  hand  or  push  car.  The 
tool  house  should  be  placed  convenient  to  that  occupied  by 
the  section  foreman,  so  that  all  tools  and  material  may  be 
near  his  hand  either  for  repair  or  inspection,  or  for  use  in 
case  of  an  emergency.  All  tools  and  material  contained  in 
the  house  should  be  kept  in  perfect  order  and  repair.  A 
building  fully  meeting  the  requirements  of  a  tool  house  is 
shown  in  Fig.  639.  It  should  rest  upon  a  substantial  found- 
ation of  masonry,  and  stand  fully  12  inches  above  the  sur- 
face of  the  ground,  so  as  to  allow  ample  circulation  of  air 
among  the  floor  timbers.  At  one  end  of  the  house  is  a 
work  bench  fitted  with  a  vise,  together  with  wrenches,  ham- 
mers, hand  saws,  punches,  and  any  other  tools  necessary  in 
making  repairs  of  tools  or  track. 

The  hand  and  push  cars  rest  upon  a  permanent  track, 
shown  at  a.  They  are  admitted  through  a  sliding  door 
shown  in  detail  at  A. 

A  device  for  transferring  the  hand  car  to  the  tool  house 
track  is  shown  at  C.  It  consists  of  two  oak  pieces  b  and  c 
which  serve  as  rails.  They  are  held  at  gauge  by  the  cross- 
piece  d  and  the  bolster  e,  which  are  bolted  to  the  strips.  A 
pin  passes  through  the  bolster  ^  into  a  socket  in  the  cast-iron 
portable  pedestal /"on  which  the  frame  revolves.  In  using, 
the  pedestal  is  placed  upon  a  tie  with  the  pieces  r,  d  lying  di- 
rectly upon  the  rails.  The  hand  car  is  then  run  upon  the  frame, 
which  is  revolved  so  as  to  connect  with  the  tool  house  track. 

The  tool  house  should  be  well  provided  with  racks,  upon 
which   the  various  tools  of  the  section   may  be  safely  and 


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1292  RAILROAD    STRUCTURES. 

economically  stored.  Hooks  of  iron  or  of  wood  nailed  to  the 
sides  of  the  house  are  especially  handy  for  hanging  up 
shovels.  A  locker  built  under  the  work  bench  is  useful  for 
storing  lanterns  and  oil  cans. 

The  plan  shown  is  in  detail,  so  that  it  may  be  used  as  a 
guide  for  any  who  wish  to  build  a  safe  and  economical  tool 
house.  A  section  through  the  door  is  shown  in  detail  at  B. 
The  roof  covering  is  of  corrugated  iron,  which  also  serves  as 
a  protection  against  fire. 

1823*  Section  Dwelling  Houses. — Dwelling  houses 
for  section  men  should  be  substantial,  neat,  and  of  moderate 
size  and  cost.  A  house  meeting  these  requirements  is  shown 
in  Figs.  G40  and  641.  It  has  a  balloon  frame,  is  strong, 
and  may  be  undertaken  and  built  by  any  carpenter  of  aver- 
age intelligence.  It  provides  ample  accommodation  for  a 
family  of  eight  persons,  and  will  contain  twelve  with  but 
little  crowding.  The  outer  walls  and  partitions  consist  of 
two  courses  of  inch  boards  nailed  vertically  to  the  frame. 
They  should  be  surfaced  on  one  side,  ship  lapped,  and 
well  seasoned  before  being  put  in  place.  This  gives  a 
smooth  surface  on  both  sides  of  the  walls,  and  takes  paint 
well. 

Door  and  window  casings  should  be  of  pine.  The  ground 
floor  is  of  material  similar  to  the  walls,  excepting  that  the 
floor  boards  should  be  tongued  and  grooved.  Complete 
framing  plans  are  shown,  and  will  serve  as  a  guide  to  those 
undertaking  similar  work.  The  cross-section  A  B  shows 
the  arrangement  of  the  stairs  and  spacing  of  floors.  A 
framing  plan  of  the  second  floor  is  shown  at  E^  and  of  the 
first  or  ground  floor  at  G.  A  detail  of  the  roof  frame  of 
the  main  body  of  the  house  is  shown  at  F^  and  of  the  roof 
of  the  addition  at  H.  A  detail  of  the  sill  and  floor  joist  is 
shown  at  A',  and  of  a  door  casing  at  L.  The  roof  covering, 
like  that  of  the  tool  house,  should  be  of  corrugated  iron. 

1824.  "Watchman's  Shanty.  — A  watchman's  shanty 
should  be  large  enough  to  comfortably  accommodate  one 
man,  no  more.    This  will  include  space  for  a  stove  for  warming 


Section  through  AB. 


Section  through  CD. 


Fig.  Ml. 


1294  RAILROAD    STRUCTURES. 

the   building  in  winter.     A  general  plan  for  a  watchman's 


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Fig   642. 


shanty  is  given  in  Fig.  G42,  which  is  sufficiently  detailed  for 
practical  use. 


A   SERIES 


OF 


QUESTIONS   AND    EXAMPLES 

Relating  to  the  Subjects 
Treated  of  in  Vol.  II, 


It  will  be  noticed  that,  although  the  various  questions 
are  numbered  in  sequence  from  614  to  1082,  inclusive,  these 
questions  are  divided  into  seven  different  sections,  corre- 
sponding to  the  seven  sections  of  the  preceding  pages  of  this 
volume.  Under  the  heading  of  each  section  are  given,  in 
parentheses,  the  numbers  of  those  articles  which  should  be 
carefully  studied  before  attempting  to  answer  any  question 
or  to  solve  any  example  occurring  in  the  section. 


SURVEYING, 

(ARTS.  1180-1308.) 


Note. — The  examples  given  in  this  subject  are  similar  to  those 
arising  in  field  and  office  practice,  and  the  answers  given  have  the 
same  degree  of  accuracy  as  required  in  practical  operations.  When 
the  answer  contains  a  decimal  fraction,  the  student  should  carry  out 
the  result  to  one  place  greater  than  required  in  the  answer  given. 
If  the  figure  so  obtained  is  less  than  5,  it  is  ignored;  if  it  is  5  or 
greater,  add  1  to  the  preceding  figure  for  the  correct  answer. 

(614)  In  a  triangle  whose  angles  are  A,  B,  and  C,  what  is 
each  angle  if  A  is  twice  and  B  three  times  C  ? 

(615)  Required,  each  angle  of  an  isosceles  triangle,  if  the 
unequal  angle  equals  twice  the  sum  of  the  other  two. 

(616)  Construct  a  square  whose  diagonal  is  3.5  inches. 
What  is  the  length  of  its  side  ?  Ans.  2.475  in.,  nearly. 

(617)  The  diagonal  of  a  rectangle  is  3  inches,  the  shorter 
side  1.5  inches;  construct  it  and  fitnd  its  area. 

Ans.  Area  =  3.897  in. 

(618)  Through  two  points  1.5  inches  apart,  draw  a  circle 
having  a  diameter  of  3.5  inches. 

(619)  At  any  point  on  a  straight  line,  construct  an  angle 
of  30°. 

(620)  A  line  2  inches  long  is  met  at  one  extremity  by  a 
second  line,  making  with  it  an  angle  of  30° ;  find  the  center 
of  the  circle  of  which  the  first  is  a  chord  and  the  second 
a  tangent. 

(621)  At  a  point  on  any  straight  line  construct  an  angle 
of  45°. 

(622)  Construct  an  isosceles  triangle  with  a  base  of  3 
inches  and  a  vertical  angle  of  00°. 

(623)  Draw  a  figure  showing  two  parallel  lines  cut  by  a 
secant,  and  name  all  the  angles  thus  formed. 


1298  SURVEYING. 

(624)  What  is  meant  by  similar  polygons  ?  Give  exam- 
ples. 

(G25)  One  of  the  angles  of  a  triangle  is  30°;  one  of  the 
including  sides  5  inches,  and  the  difference  of  the  other  two 
sides  1.5  inches;  construct  the  triangle. 

(G2G)  How  is  the  north  end  of  the  magnetic  needle 
determined  ? 

(627)  How  is  the  compass  circle  divided,  and  how  are  the 
degrees  numbered  ? 

(628)  Explain  why  the  east  and  west  points  of  the  com- 
pass plate  are  marked  the  reverse  of  their  natural  order. 

(629)  What  are  the  principal  defects  of  the  compass  ? 

(630)  What  constitutes  a  course  ? 

(631)  How  is  the  bearing  of  a  line  taken  and  how 
checked  ? 

(632)  How  is  a  line  run  by  backsights  ? 

(633)  Define  local  attraction  and  state  by  what  it  is 
usually  caused. 

(634)  Explain  the  difference  between  the  magnetic 
meridian  and  a  true  meridian. 

(635)  What  is  meant  by  the  declination  of  the  needle  ? 

(636)  How  is  a  true  meridian  established  ? 

(637)  Explain  the  difference  between  a  magnetic  bearing 
and  a  true  bearing. 

(638)  {a)  The  declination  is  3°  15' east;  what  are  the 
true  bearings  of  the  following  lines,  their  magnetic  bearings 
being : 


Magnetic  Bear- 
ing. 

True 
Bearing. 

N  15°  .20'  E 

N  88°  50'  E 

N  20°  40'  W 

N  50°  20'  E 

SURVEYING. 


1299 


{d)  The   declination   is   5°   10'  west;    required,  the   true 
bearing  of  the  following  lines: 


Magnetic  Bear- 
ing. 

True 
Bearing. 

N    7°20'W 

N  45°  00'  E 

S  15°  20'  E 

S     2°  30'  W 

(639)  How  are  stations  in  railroad  surveys  numbered, 
and  what  is  the  interval  between  stations  ? 

(640)  What  are  the  special  advantages  which  the  com- 
pass offers  in  preliminary  railroad  surveys,  and  what 
conditions  should  determine  its  rejection  for  such  work  ? 

(641)  Describe  the  process  of  chaining. 

(642)  Plat  the  following  compass  notes: 


Station. 

Bearing. 

60  +  20 

50  +  90 

N  80°  15'  E 

44  +  50 

S45°  55' E 

28  +  13 

S11°25'E 

20+11 

S  76°  30'  E 

10  +  89 

N79°  25' E 

5  +  20 

N  40°  50'  E 

0 

N  10°  10'  E 

(643)  Describe  the  vernier.  A  vernier  is  described  as 
reading  to  single  minutes.  Make  a  drawing  of  such  a 
vernier  and  explain  its  use. 

(644)  Explain  the  different  adjustments. 


1300 


SURVEYING. 


(645)  How  is  a  line  prolonged  by  backsight  ?  by 
foresight  ? 

(646)  Explain  by  figure  the  process  of  double  centering, 
and  state  its  advantages, 

(647)  Define  a  horizontal  angle  and  its  measurement. 

(648)  Of  what  value  is  the  magnetic  needle  where  all 
angles  are  read  with  the  vernier  ? 

(649)  Explain  by  example  what  is  meant  by  calculated 
or  deduced  bearings. 

(650)  The  magnetic  bearing  of  a  line  is  N  55°  15'  E,  and 
an  angle  of  15°  17'  is  turned  to  the  right;  what  is  the 
bearing  of  the  second  line  ?  \ 

(651)  The  magnetic  bearing  of  a  line  is  N  80°  11'  E,  and 
an  angle  of  22°  13'  is  turned  to  the  right;  what  is  the 
bearing  of  the  second  line  ? 

(652)  The  magnetic  bearing  of  a  line  is  N  13°  15'  W,  and 
an  angle  of  40°  20'  is  turned  to  the  left;  what  is  the  bearing 
of  the  second  line  ? 

(653) 


Station. 

Deflection. 

Mag.  Bearing. 

Ded.  Bearing. 

54  +  25 

49  +  20 

L.    25°  14' 

S  25°  40'  W 

44  +  80 

L.  10°  47' 

S  50°  50'  W 

33  +  77 

R.  16°  55' 

S  61°  45'  W 

.  25  +  60 

R.  24°  40' 

S  44°  50'  W 

16  +  20 

L.   15°  35' 

S  20°  00'  W 

8  +  90 

R.  10°  15' 

S  35°  50'  W 

4  +  40 

R.  15°  10' 

S  25°  20'  W 

0 

S  10°  15'  W 

SURVEYING. 


1301 


Calculate  the  bearings  of  the  foregoing  transit  notes  of  an 
angle  line  and  plat  them  to  a  scale  of  400  feet  to  the  inch, 
showing  the  direction  of  the  magnetic  meridian. 

(654)  The  line  of  survey  A  B 
(see  Fig.  12)  crosses  a  stream 
C  D  too  wide  for  direct  meas- 
urement. The  angle  A  is  80° 
20',  the  angle  E  is  60°  15', 
the  side  A  E  \^  415  feet ;  re- 
quired, the  angle  B  and  the 
side  A  B. 

Angle  B  =  39°  25'. 

Side  ^i?=  567.44  ft. 


Ans. 


(655) 


Pig.  12. 

An  obstacle.  Fig.  13,  lies  in  the  path  of  survey 
A  B.  Show  how  the  equilat- 
eral triangle  may  be  used  in 
passing  the  object  and  prolong- 
ing the  line  of  survey. 


Fig.  13. 


(656)     What   is   an    intersec- 
tion   of   tangents  ?     How    is   it 
made  and  the  angle  of  intersection  measured  ? 

(657)  Define  curve  and  tangent  as  applied  to  railroad 
engineering. 

(658)  Name  and  describe  the  three  classes  of  curves  used 
in  railroad  building. 

(659)  What  is  the  amount  of  the  divergence  of  two  lines 
100  feet  in  length  and  forming  an  angle  of  1°  with  each 
other  ? 

(660)  What  is  the  unit  curve  employed  in  railroad 
building  ?     Define  it. 

(661)  Define  a  five-degree  (5°)  curve. 

(662)  What  is  the  ratio  of  the  degree  of  curve  to  the 
deflection  angle  ? 


1303 


SURVEYING. 


(GG3)     What  is  the  formula  for  finding  the  radius^   the 

deflection  angle  be- 
ing given  ? 

(664)  What  is  the 
formula  for  finding 
the  length  of  any 
chord,  the  radius 
and  deflection  angle 
being  given  ? 

(GG5)  What  is  the 
tangent  distance, 
and  what  formula  is 
used  in  finding  it  ? 

(666)     The      tan- 
FiG.  14.  gents  A  ^  and  C  D, 

in  Fig.  14,  intersect  at  some  inaccessible  point  E.  The  angle 
A  is  22°  10',  the  angle  C  23°  15',  and  the  side  A  C  253.4 
feet ;  required  the  angle  of  intersection  C  E  /%  and  the  sides 
A  EznA  E  C.  (  Angle  CEE=  45°  25'. 

Ans.  ]         Side  A  E  =  140.44  ft.,  nearly. 
(         Side  CE=  134.24  ft.,  nearly. 

(667)  The  angle  of  intersection  of  two  tangents  is  35°  10' ; 
the  degree  of  curve  is  G°  15';  what  is  the  tangent  distance  ? 

Ans.  290. GG  ft.,  nearly. 

(668)  The  angle  of  intersection  is  14°  12' ;  the  degree  of 
curve,  3°  15';  what  is  the  tangent  distance  ? 

Ans.  219.62  feet. 
How  is  the  length  of  curve  found  ? 
The  angle  of  intersection  is  30°  45';  the  degree  of 
15';  what  is  the  length  of  the  curve  ? 

Ans.  585.71  feet. 
The  angle  of  intersection  is  33°  06' ;  the  station  of 
the  point  of  intersection,  20 -p  37.8;  the  degree  of  curve, 
5°;  what  is  the  station  of  the  P.  C,  length  of  curve  and 
station  of  the  P.  T.  ?  t  P.  C.  =  16  +  97. 17. 

Ans.  ■)  Length  of  curve  =  662  ft. 
(  P.  T.  =23  +  59.17. 


(669) 

(670) 

curve,  5*^ 

(671) 


SURVEYING.  130:i 

(072)  The  angle  of  intersection  is  20**  10';  the  tangent 
distance,  291.  IG  feet ;  required, the  radius  and  degree  of  curve. 

^^^   j  Radius  =  1,(;:57. 29  feet. 
I  Degree  of  curve,  3°  30'. 

(673)     What  is  the  formula  for  the  chord  deflection  ? 

(074)  What  is  the  ratio  of  the  chord  deflection  to  the 
tangent  deflection  ? 

(675)  The  degree  of  curve  is  7°;  what  is  the  deflection 
angle  for  a  chord  of  48.2  feet  ?  Ans.   1"  41.22'. 

(676)  The  degree  of  curve  is  6°  15' ;  what  is  the  deflection 
angle  for  a  chord  of  72.7  feet  ?  Ans.   2°  16.3'. 

(677)  The  degree  of  curve  is  5°  30' ;  what  is  the  tangent 
deflection,  or  offset,  for  50  feet  ?  Ans.   1.199  feet. 

(678)  The  degree  of  curve  is  4°  15' ;  what  is  the  chord 
deflection  for  35.2  feet  ?  Ans.   0.919  foot. 

(679)  What  is  the  radius  of  a  3°  10'  curve  ? 

Ans.   1,809.57  feet. 

(680)  Two  lines  of  equal  length  forming  an  angle  of  1° 
with  each  other  diverge  18.22  feet;  what  are  the  lengths  of 
the  lines?  .         j  By  trigonometry,  1,043.53  feet. 

(  By  practical  method,  1,044.13  feet. 

(681)  A  curve  is  606.25  feet  in  length;  the  angle  of  inter- 
section is  24°  15' ;  what  is  the  degree  of  the  curve  ? 

Ans.  4°. 

(682)  What  are  the  different  processes  of  leveling  ? 
Define  them. 

(683)  Describe  the  Y  level  and  explain  its  adjustments. 

(684)  The  level  rod  is  held  300  feet  from  the  instrument; 
the  reading  is  6.81  feet.  After  causing  the  level  bubble  to 
move  over  one  division  of  the  scale,  the  reading  is  6.84; 
what  is  the  radius  of  the  bubble  tube  ?  Ans.  100  feet. 

(685)  What  is  meant  by  the  power  and  definition  of  a 
telescope  ? 


1304  SURVEYING. 

(G8G)     Describe  the  self-reading  leveling  rod. 

(687)  The  elevation  of  the  point  where  the  backsight  is 
taken  is  61.84  feet,  the  backsight  is  11.81  feet,  and  the  fore- 
sight to  a  turning  point  (T.  P.)  is  0.49  foot;  what  is  the 
elevation  of  the  T.  P.  ?  Ans.  73. 16  feet. 

(688)  Define  a  datum  line. 

(689)  What  are  turning  points  ? 

(690)  What  are  bench  marks  ? 

(691)  What  are  the  principal  sources  of  error  in  taking 
levels  ? 

(692)  Explain  the  process  of  checking  level  notes. 

(693)  What  is  a  profile  ? 

(694)  Define  a  1  per  cent,  grade. 

(695)  The  elevation  of  the  grade  at  Station  GO  is  126.50; 
between  Stations  66  and  100  there  is  an  ascending  grade 
of  1.25  per  cent.;  what  is  the  elevation  of  the  grade  at 
Station  93  ?  Ans.  160.25  feet. 

(696)  What  is  topographical  surveying  ? 

(697)  The  elevation  of  a  station  is  56.5  feet;  the  ground 
on  the  left  falls  10.3  feet  in  a  distance  of  73  feet,  where  the 
slope  changes,  giving  a  fall  of  16.4  feet  in  a  distance  of  56 
feet.  On  the  right  the  ground  rises  11.4  feet  in  a  distance 
of  84  feet,  where  the  slope  changes,  giving  a  rise  of  8.8 
feet  in  a  distance  of  96  feet.  How  are  these  slopes  recorded 
in  the  topographer's  book  ?  How  many  10-foot  contours 
are  included  by  the  side  slopes,  and  what  are  their  eleva- 
tions, the  contours  being  placed  at  even  decimal  intervals 
of  10  feet  ?  What  are  the  several  distances  of  the  contours 
from  the  center  line  ? 

(698)  Work  out  the  elevation  of  the  following  notes; 
check  the  notes,  plat  them  in  a  profile,  and  draw  a  descend- 
ing grade    line   of   80  feet  to   the    mile,  and    place  in  the 


SURVEYING. 


1:^05 


column  headed  Grade  the  elevation  of  the  grade  of  each 
station  given  in  the  station  column: 


Station. 

Rod 
Read- 
ing. 

Ht. 
Instru- 
ment. 

Eleva- 
tion. 

Grade. 

Remarks. 

B.M.+5.53 

101.42 

B  M.  on  Poplar  tree  10  ft. 
left;  Sta.  40. 

40 

G.4 

162.0 

41 

7.2 

41  +  60 

10.9 

42 

8.6 

43 

8.8 

T.  P. - 

8.66 

+ 

2.22 

44 

4.8 

45 

6.3 

46 

8.8 

47 

9.9 

48 

11.1 

T.  P. - 

11.24 

+ 

3.30 

49 

4.7 

50 

7.1 

51 

8.7 

52 

9.8 

53 

10.9 

T.  P.- 

11.62 

(699)     The  ground  to  the  right  of  the  center  line  has  an 
ascending  slope  of  11°  for  a  distance    of  120  feet,   and  to 


130G 


SURVEYING. 


the  left  of  the  center  line  a  descending  slope  of  9*^  for  a 
distance  of  117  feet,  where  the  slope  changes  to  a  descend- 
ing slope  of  0°  for  a  distance  of  G5  feet;  how  are  the  slopes 
recorded  in  the  topographer's  book  ?  If  the  elevation  of 
the  ground  at  the  center  line  is  75.0  feet,  how  many 
5-foot  contours  are  included  by  the  given  slopes,  and  what 
are  their  respective  distances  from  the  center  line  ? 

(700)  The-angle  of  slope  is  3° ;  what  is  the  horizontal 
distance  for  a  rise  of  10  feet  ? 

(701)  An  instrument  is  stationed  at  A,  Fig.  15,  100  feet 
from  the  base  of  a  church  spire  B  C.     The  horizontal  line 


Fig.  16. 


of  sight vi  C  from  the  instrument  is  5  feet  above  the  base 
of  the  spire,  which  at  that  point  is  30  feet  in  diameter. 
The  angle  C  A  B  is  45*  20';  required,  the  height  of  the 
spire.  Ans.  121.345  feet. 

(702)     The   height  of    barometer  //  at    lower    station  is 


SURVEYING.  1307 

29.40  in. ;  the  temperature  /  =  T4'';  the  height  of  barometer 
H  at  the  higher  station  is  20.05  in.,  and  the  temperature 
/'  =  58° ;  what  is  the  difference  in  elevation  ? 

Ans.  2,454  feet. 

(703)  What  is  hydrographic  surveying  ? 

(704)  What  stage  of  tide  is  the  basis  tor  all  soundings  ? 

(705)  What  is  a  tide  gauge  ? 


LAND  SURVEYING. 

(ARTS.  1309-1344.) 


(706)  What  are  the  names  of  the  general  divisions  into 
which  the  public  lands  of  the  United  States  are  divided  ? 

(707)  Give  the  dimensions  and  contents  of  each. 

(708)  {a)  Define  a  Principal  Meridian,  (d)  How  is  it 
established  .''     (c)  What  boundaries  are  marked  on  it  ? 

(700)  What  causes  convergency  of  meridians^  and  what 
effect  does  such  convergency  have  upon  the  boundary  lines 
of  the  Government  surveys  ? 

(710)  {a)  What  are  Standard  Parallels  ?  {b)  What  is 
their  object  ?     (r)  What  boundaries  are  marked  on  them  ? 

(711)  How  are  townships  described  with  reference  to 
Base  Line  and  Principal  Meridian  ?  Illustrate  by  a 
diagram. 

(712)  Show  by  a  diagram  how  township  lines  are  run  and 
the  order  of  the  survey. 

(713)  Explain  by  figure  the  terms  random  line  and  true 
line. 

(714)  How  are  excesses  or  deficiencies  of  measurement 
disposed  of  in  townshiping  and  sectioning  ? 

(715)  Show  by  a  diagram  the  subdivisions  of  townships 
and  the  order  of  survey. 

(71G)  {a)  Define  vicandcring  as  applied  to  Government 
surveys,  {b)  In  mapping,  what  use  is  made  of  meander 
lines  ?     (f)  How  are  islands  located  ? 

(717)  What  is  a  line  tree,  how  is  it  marked,  and  how  are 
trees  on  either  side' of  the  line  of  survey  marked  ? 


1310 


LAND    SURVEYING. 


(718)  How  is  a  boundary  corner  in  a  timbered  country 
marked  ? 

(719)  Describe  the  township  corner-post  or  corner-stone. 
How  is  it  set,  and  how  marked  ? 

(720)  Describe  a  section  corner,  and  explain  how  it  is  set 
and  marked. 

(721)  How  are  mound  corners  constructed  ? 

(722)  What  are  double  corners^  where  are  they  found, 
and  how  are  they  designated  ? 

(723)  In  running  township  and  section  lines,  "what 
account  should  the  surveyor  take  of  the  topography  of  the 
country  ? 

(724)  What  are  the  various  field  books  used  in  the  survey 
of  Government  lands  ? 

(725)  State  why  the  retracing  of  old  lines  or  original 
surveys  is  so  difficult. 

(72G)  Suppose  the  original  notes  of  a  farm  survey  are 
the  following,   and  suppose  that  only  two  of  the  original 

-  corners,   viz.,  B  and  C^  re- 


Stations. 


A 
B 
C 
D 


Bearings. 


N  3ir  W 
N  62°  E 
S    36°     E 

S   45r  w 


Distances. 


main,  and  that  we  find  the 

~Zr,    ~.        present  bearing  from  B  to  C 
10.4  chains.     *^  ° 

9.2  chains.  ^^  ^   ^^     ^^    ^'  ^^^   "^^X  ^^ 

7.6  chains,  determine  the  magnetic  vari- 

10.0  chains,  ation,  and  what  will   be  the 

•  =  corrected  bearings  by  which 


we  may  restore  the  original  boundaries  ? 

(727)  How   are   boundary   lines   straightened   and  new 
corners  established  where  old  ones  are  obliterated  ? 

(728)  What  are  witness  trees,  and  how  are  they  marked  ? 
(720)     Explain   by   a  figure   the   triangular   method    of 

calculating  areas. 

(730)  Explain   by   a   figure  the   trapezoidal   method  of 
calculating  areas. 

(731)  Define  {a)  the  latitude  of  a  point;  {b)  the  longi- 


LAND    SURVEYING. 


1311 


tude  of  a  point;    (c)  the   latitude  of   a  line,   and  {d)  the 
departure  of  a  line. 

(732)  The  line  A  B,  in  Fig.  IG,  has  a  bearing  of  N  30°  E 
and  a  length  of  187  ft.     Complete  the  figure, 
showing  the  latitude  and  departure  of  A  B, 
and  calculate  their  respective  lengths  by  means 
of  a  table  of  sines  and  cosines. 

(733)  Describe  a  traverse  table. 

(734)  The  bearing  of  a  line  is  N  23^°  E ; 
its  length  is  423  ft. ;  calculate  its  latitude  and 
departure  by  the  use  of  a  traverse  table,  and 
explain  the  process. 

(735)  The  length  of  a   line  is  225  ft. ;  its 
bearing  is  40° ;  what  are  the  latitude  and  de- 
parture of  the  line,  and  what  is  the  relation 
of  that  latitude  and  departure  to  the  latitude  and  departure 
of  the  complement  of  the  given  bearing  ? 

(736)  How  are  latitudes  and  departures  applied  in  testing 
the  accuracy  of  a  survey  ? 

(737) 


Fig.  16. 


Stations. 

Bearings. 

Distances. 

1 

N  31i°  W 

10.40  chains. 

2 

N62°    E 

9.20  chains. 

3 

S  36°    E 

7.60  chains. 

4 

S  45i°  W 

10.00  chains. 

Calculate  the  latitudes  and 
departures  of  the  courses 
in  the  accompanying  ex- 
ample, and  balance  them, 
giving  all  the  steps  of  the 
process. 


(738)  Calculate  the  total  latitudes  and  departures  from 
Station  2,  and  from  them  make  a  plat  of  the  survey 
explaining  the  different  steps  in  the  process,  , 

(739)  What  is  the  longitude  of  a  line  ? 

(740)  What  is  the  general  rule  for  the  double  longitude  of 
any  course  of  a  given  survey  ? 

(741)  Illustrate  by  a  figure  the  method  of  computing  areas 
by  double  longitudes. 

(742)  What  are  north  products  and  what  south  products  ? 


1312 


LAND   SURVEYING. 


(743)  If  the  double  longitude  is  negative  and  the  corre- 
sponding latitude  positive,   is  the  product  north  or  south  ? 

(744)  How  is  the  most  easterly  or  most  westerly  station 
of  a  survey  found  ? 

(745) 


(740) 


(747) 


Distances. 

12.41  chains. 
5.86  chains. 
8.25  chains. 
4.24  chains. 


Stations. 

Bearings. 

Distances. 

1 

S  21i° 

W 

17.62  chains. 

2 

S  34° 

w 

10.00  chains. 

3 

N56° 

w 

14.15  chains. 

4 

N34° 

E 

9.76  chains. 

5 

N67° 

E 

2.30  chains. 

6 

N23° 

E 

7.03  chains. 

7 

NlSr 

E 

4.43  chains. 

8 

S  76i° 

E 

12.41  chains. 

Stations. 

Bearings. 

Distances. 

1 

N 

18i" 

E 

1.93  chains. 

2 

N 

9° 

W 

1.29  chains. 

3 

N 

14' 

W 

2.71  chains. 

4 

N 

74° 

E 

0.95  chains. 

5 

S 

48i° 

E 

1.59  chains. 

6 

S 

14i' 

E 

1.14  chains. 

< 

s 

i9r 

E 

2.15  chains. 

8 

s 

23i° 

W 

1.22  chains. 

9 

s 

5° 

W 

1.40  chains. 

10 

s 

.30' 

W 

1.02  chains. 

11 

s 

8ir 

W 

0.69  chains. 

12 

N 

32r 

W 

1.98  chains. 

Find  the  area  by  double 
longitudes,  giving  all  the 
intermediate  steps. 

Ans.  4  A.  2  R.  35.8  P. 


Find  area  by  double  longi- 
tudes. 

Ans.  33  A.  OR.  8.8  P. 


Find  area  by  double  longi- 
tudes. 


Ans.   1  A.  1  R.  27|  P. 


LAND   SURVEYING.  1313 

(748)  In  laying  out  town  sites,  what  matters  should  first 
be  considered  ? 

(749)  (a)  How  should  the  grades  of  streets  be  arranged 
with  reference  to  drainage  ?  (d)  with  reference  to  topog- 
raphy ? 

(750)  How  should  dase  lines  be  located  with  reference  to 
railroad  lines  ? 

(751)  What  is  the  usual  order  of  preliminary  survey  ? 

(752)  How  are  measurements  to  be  made  ? 

(753)  Give  a  brief  sketch  illustrating  the  mode  of  laying 
out  base  lines  and  subdivisions. 

(754)  How  are  base  lines  rendered  permanent  ? 

(755)  What  important  requirement  is  met  by  locating 
street  corners  by  intersecting  lines  ? 


RAILROAD  LOCATION 

(ARTS.  1391-1452.) 


(756)  What  is  the  first  duty  of  the  chief  engineer  ? 

(757)  What  are  terminals  ? 

(758)  From  what  sources  does  the  engineer  gain  infor- 
mation of  the  section  of  country  to  be  operated  in  ? 

(759)  What  is  the  prime  object  in  building  a  railroad  ? 

(700)  What  is  your  idea  of  the  distinction  between 
matters  which  are  financially  important  and  those  which 
are  physically  important  ? 

(7G1)  What  is  the  average  continuous  cut  and  fill,  with 
proportionate  amount  of  masonry  that  will  equal  the  cost 
of  the  superstructure,  i.  e.,  ties,  rails  and  fastenings,  and 
ballast  ? 

(702)  What  are  the  main  sources  of  traffic,  and  what 
measures  should  be  taken  to  reach  them  ? 

(763)  What  knowledge  will  enable  the  engineer  to  prop- 
erly estimate  the  comparative  cost  of  different  lines  ? 

(764)  Ordinarily,  how  many  different  routes  will  it  be 
necessary  for  the  engineer  to  examine,  and  what  are  the 
considerations  which  narrow  the  field  of  operations  ? 

(705)  Define  a  reconnaissance,  and  its  relative  importance 
to  other  departments  in  the  work  of  location. 

(700)  What  assistance  will  the  engineer  requiie  in  ma- 
king the  reconnaissance  ?  How  will  he  conduct  the  same, 
and  what  range  of  country  should  he  cover  ? 

(767)     Of  what  use  is  the  hand  level  ? 


1316  RAILROAD   LOCATION. 

(708)  What  records  should  be  kept  ?  What  do  the  sizes 
and  rate  of  current  of  different  streams  indicate  ? 

(7G9)  Give  examples  of  the  deceptive  appearance  of 
country,  and  state  how  the  eye  tends  to  exaggerate  offsets, 
angles,  and  distances. 

(770)  In  general,  how  should  local  reports  and  estimates 
of  country  be  regarded  ? 

(771)  Are  conditions  often  met  where  but  one  line  is 
possible  ? 

(772)  What  advantages  do  valleys  possess  over  ridges  or 
rolling  country  ? 

(773)  What  is  the  organization  of  a  location  party  ?  what 
the  necessary  outfit  ? 

(774)  Under  what  conditions  should  the  compass  be 
used  ? 

(775)  How  is  the  starting  point  usually  determined  with 
reference  to  other  fixed  lines  or  boundaries  ? 

(77G)  Describe  the  order  of  conducting  the  preliminary 
survey. 

(777)  Describe  the  work  of  the  level  and  topographical 
parties. 

(778)  What  constitutes  the  office  work  of  the  preliminary 
survey  ? 

(779)  Define  spur  lines. 

(780)  Define  a  gradient,  and  state  what  considerations 
modify  or  determine  gradients. 

(781)  What  conditions  limit  curvature,  and  what  lati- 
tude should  the  engineer  be  allowed  in  their  use  ? 

(782)  What  are  temporary  lines,  and  when  and  where 
may  they  be  used  to  advantage  1 

(783)  What  is  a  paper  location  ? 

(784)  Describe  how  field  notes  are  made  up  from  the 
paper  location. 

(785)  What  is  a  paper  location  profile  ? 

(786)  What  constitutes  the  location  party  ? 


RAILROAD    LOCATION.  1317 

(787)  A  curve  whose  intersection  angle  is  32°  30'  is  run 
in,  and  it  is  found  that  its  tangent  is  parallel  to  the  required 
tangent,  but  20  ft.  outside  of  it.  How  far  backward  must 
the  P.  C.  be  moved  in  order  that  the  tangent  may  take  its 
proper  position  ?  Ans.  48.39  ft. 

(788)  If  the  intersection  angle  is  41°  20'  and  the  follow- 
ing tangent  is  parallel,  but  falls  13.4  ft.  within  the  required 
tangent,  how  far  forward  must  we  move  the  P.  C.  ? 

Ans.  20.29  ft. 

(789)  A  compound  curve  in  which  the  first  curve  is  6° 
and  the  second  curve  9°,  with  an  intersection  angle  of 
34°  20',  terminates  in  a  tangent  parallel  to  but  26.4  ft.  with- 
out a  given  required  tangent;  how  far  backward  must  the 
P.*  C.  C.  be  moved  in  order  that  the  tangent  may  take  the 
prescribed  position  ?  Ans.   128.33  ft. 

(790)  A  compound  curve  in  which  the  first  curve  is  3° 
and  the  second  curve  7°,  with  an  intersection  angle  of  36° 
40',  terminates  in  a  tangent  parallel  to  but  32.4  ft.  within  a 
given  required  tangent;  how  far  forward  must  the  P.  C.  C. 
be  moved  in  order  that  the  tangent  may  take  the  prescribed 
position?  Ans.   98.33ft. 

(791)  A  compound  curve  in  which  the  first  curve  is  4°  and 
the  second  curve  0°,  with  an  intersection  angle  of  37°  10'. 
terminates  in  a  tangent  parallel  to  but  56  ft.  without  a  given 
required  tangent;  how  far  backward  must  the  P.  C.  C.  be 
moved  in  order  that  the  tangent  may  take  its  required 
position?  Ans.  250.4  ft. 

(792)  A  compound  curve  in  which  the  first  curve  is  8° 
and  the  second  curve  3°,  with  an  intersection  angle  of  28°  40', 
terminates  in  a  tangent  parallel  to  but  25.4  ft.  without  the 
required  tangent;  how  far  forward  must  the  P.  C.  C.  be 
moved  in  order  that  the  tangent  may  take  its  proper 
position  ?  Ans.  33.33  ft. 

(793)  A  compound  curve  in  which  the  first  curve  is  9" 
and  the  second  4°,  wkh  an  intersection  angle  of  36°  15',  ter- 
minates in  a  tangent   parallel    to    but    33    ft.    within    the 


1318  RAILROAD   LOCATION. 

required  tangent ;  how  far  backward  must  we  move  the  P.  C.  C. 
in  order  that  the  tangent  may  take  its  required  position  ? 

Ans.  42. 78  ft. 

(794)  The  P.  C.  and  P.  T.  of  a  7°  curve  having  been 
established,  it  is  found  that  obstacles  lie  in  the  path  of  the 
curve,  and  it  is  decided  to  run  a  parallel  curve  100  feet  with- 
in the  7°  curve  from  which  the  stations  on  the  required 
curve  may  be  located ;  what  will  be  the  length  of  each  chord 
corresponding  to  full  stations  on  the  required  7°  curve  ? 

Ans.   87.79  ft. 

(795)  Two  angles  of  intersection  are  34°  20'  and  41°  30; 
the  distance  between  the  points  of  intersection  is  1,011  feet; 
what  is  the  radius  of  the  easiest  reverse  curve  which  will 
unite  the  given  tangents  ? 

Ans.   Radius  =  1,469.94  ft.  =  3°  53.9'  curve. 

(796)  Two  angles  of  intersection  are  20°  14'  and  41°  08'; 
the  distance  between  points  of  intersection  is  816  feet;  what 
is  the  radius  of  the  easiest  reverse  curve  which  will  unite  the 
tangent  ?  Ans.   Radius  =  1,473.88  ft.  =  3°  53.3'  curve. 

(797)  The  angle  E  B  C  \n  Fig.  17  =  28°  40',  the  angle 
FC  B=dO°  16',  and  the  line  B  C  =  470  ft. ;  required,  the 


Fig.  17. 

radius  of  the  curve  which  will  be  tangent  to  the  lines  A  B, 
B  C,  and  C  D.  Ans.   Radius  =  893.6  ft.  =  6°  24.7'  curve. 

(798)  In  Fig.  17  let  the  angle  E  BC  =  32°  50',  the  angle 
F  C  B  —  4:1°  20',  and  the  side  B  C=  516  ft. ;  required,  the 
radius  of  the  curve  tangent  to  A  B,  B  C,  and  C  D. 

Ans.   Radius  =  768.05  ft.  =  7°  27.6'  curve. 

(799)  A  preliminary  line  crosses  a  wide  stream,  and  a 
plug  is  set  on  line  on  both  sides  of  the  river.  The  transit  is 
set  over  one  plug,  and  an  angle  of  1°  is  then  turned  from  the 


RAILROAD    LOCATION. 


1310 


line  of  survey  and  a  plug  set  directly  opposite  to  the  plug  on 
the  other  side  of  the  stream.  If  the  distance  between  these 
plugs  is  7.3  ft.,  what  is  the  w^idth  of  the  river  ? 

Ans.   418.3  ft. 

(800)  What  opportunity  does  clearing  the  right  of  way 
afford  for  bettering  the  line  ? 

(801)  How  are  transit  points  referenced,  and  what  is  the 
object  of  referencing  them  ? 

(802)  When  are  final  levels  taken  ?  Of  what  are  they 
the  basis  ? 

(803)  What  is  the  principal  effect  of  curvature  upon 
passing  trains  ?  What  are  the  usual  compensations  for 
curvature  ? 

(804)  The  location  notes  between  Stations  20  and  40  are 
as  follows  : 


Stations. 

Intersection 
Angles. 

Elevation  of  Grades. 

40 

142.50 

36  +  30  P.  T. 

• 

137.6271 

31  +  80  P.  C.  8°  L. 

36°  00' 

132.7806 

28  +  70  P.  T. 

128.6979 

24  -f  50  P.  C.  10°  R. 

42°  00' 

124.4265. 

20 

118.50 

Assuming  that  the  elevation  of  grade  of  Sta.  20  is  118.50 
ft.,  and  the  elevation  of  grade  at  Sta.  40  is  142.50  ft.,  and 
allowing  a  compensation  of  .03  ft.  per  degree,  what  are  the 
grades  for  the  tangents  and  curves,  and  what  are  the  eleva- 
tions of  grade  at  the  points  of  curve  and  tangent  on  the 
given  line  ?  Explain  the  process  by  which  the  rates  of  grade 
and  elevations  are  determined. 

(805)  When  are  vertical  curves  employed,  and  what  is 
their  object  ? 


bered  in  regular  notation  ? 


Ans. 


1320  RAILROAD   LOCATION. 

(80G)  Two  grade  lines,  the  first  an  ascending  grade  of 
1  per  cent.,  and  the  second  a  descending  grade  of  0.8  per 
cent.,  are  to  be  united  by  a  parabolic  vertical  curve  of  a 
length  of  GOO  ft.  What  is  the  value  of  a\  and  if  the  eleva- 
tion of  the  beginning  of  the  curve  on  the  ascending  grade  is 
110  ft.,  what  are  the  elevations  of  the  grades  for  the  re- 
maining stations  of  the  curve,  the  starting  point  of  the 
curve  being  Sta.  0,  and  the  remaining  stations  being  num- 

a  =  Q.\5  ft. 
Grade  at  Sta.  0  =  110  ft. 
Grade  at  Sta.  1  =  110.85  ft. 
Grade  at  Sta.  2  =  111.4  ft. 
Grade  at  Sta.  3  =  111.65  ft. 
Grade  at  Sta.  4  =  lll.G  ft. 
Grade  at  Sta.  5  =  111.25  ft. 
Grade  at  Sta.  6  =  IIO.G    ft. 

(807)  Draw  a  figure  showing  the  grade  lines  specified  in 
the  previous  question,  and  the  vertical  curve  required  to 
unite  them. 

(808)  What  is  the  usual  classification  of  materials  to  be 
handled  or  used  in  the  work  of  construction  ? 

(809)  What  are  the  usual  slopes  given  to  earth  cuts,  rock 
cuts,  and  embankments  ? 

(810)  How  is  the  line  divided  before  construction  is 
commenced,  and  what  are  the  divisions  called  ? 

(811)  What  is  the  standard  width  of  right  of  way  ? 

(812)  In  advertising  work  for  contract,  what  important 
reservation  should  the  company  make  ? 


RAILROAD  CONSTRUCTION. 

(ARTS.  1453-1502.) 


(813)  When  a  line  of  railroad  is  in  readiness  for  construc- 
tion, how  is  it  subdivided  ? 

(814)  What  are  the  duties  of  the  division  engineer  ? 

(815)  What  are  the  slopes  usually  given  in  setting  slope 
stakes  for  embankment  and  for  excavation  ? 

(81G)  The  height  of  instrument  is  127.4  feet,  the  eleva- 
tion of  grade  is  140  feet,  and  the  rod  reading  for  the  right 
slope  is  9.2  feet;  what  is  the  fill  and  the  distance  of  the  right 
slope  stake  from  the  center  line,  the  roadway  being  IG  feet 
in  width?  ^^^   j"  Fill,  21.8  feet. 

I  Side  distance,  40.7  feet. 

(817)  The  height  of  instrument  is  96.4  feet,  the  grade 
78.0  feet,  the  rod  reading  at  the  center  line  is  4.7  feet;  what 
is  the  amount  of  cutting  ?  Ans.  13.7  feet. 

(818)  With  the  same  height  of  mstrument  and  grade  as 
in  question  5  and  a  left  rod  reading  of  8.8  feet,  what  is  the 
cutting  and  the  side  distance,  the  width  of  roadway  being 
18  feet  ?  ^^^    j  Cut,  9.G  feet. 

(  Side  distance,  18.6  feet. 

(819)  How  should  the  operation  of  clearing  be  con- 
ducted ? 

(820)  Describe  the  modern  mode  of  grubbing  stumps. 

(821)  Name  the  different  classes  of  culverts. 

(822)  With  a  coefficient  of  1.8  and  a  drainage  area  of 
400  acres,  what  should  be  the  area  in  square  feet  of  a  culvert 
opening  ?  xVns.   36  square  feet. 


1322  RAILROAD   CONSTRUCTION. 

(823)  An  embankment  is  28  feet  in  height ;  a  box  culvert 
with  an  opening  3  feet  wide  and  4  feet  in  height  will  pass 
the  water.  The  covering  flags  are  1  foot  thick,  and  the 
parapet  1  foot  high.  (r?)  What  will  be  the  distance  from 
the  center  line  to  the  face  of  the  culvert  ?  (d)  What  will 
be  the  distance  from  the  face  of  the  abutment  to  the  end  of 
the  wing  walls  ? 

.         j  From  center  to  face  of  culvert,  44  ft.  4  in. 

(  From  face  of  abutment  to  end  of  wing  wall,  9  ft.  G  in. 

(824)  What  should  be  the  limit  of  the  span  of  a  box  cul- 
vert; and  when  a  greater  opening  is  required  to  pass  the 
water,  how  is  it  obtained  ? 

(825)  What  is  the  usual  foundation  for  a  box  culvert, 
and  how  is  it  prepared  ? 

(826)  What  are  some  of  the  means  employed  to  obtain  a 
secure  foundation  in  soft  or  marshy  soils  ? 

(827)  What  are  tile  culverts;  under  what  conditions  are 
they  ordinarily  employed,  and  how  are  they  built  ? 

(828)  How  should  cattle  guards  be  built  ? 

(829)  The  height  of  the  embankment  at  an  open  passage- 
way is  IG  feet;  what  should  be  the  thickness  of  the  base  of 
the  wall  directly  below  the  center  line  ?  Ans.  6.4  ft. 

(830)  Name  the  different  parts  of  an  arch. 

(831)  Name  the  different  classes  of  arches,  and  describe 
them. 

(832)  The  radius  of  a  semicircular  arch  of  cut  stone  is 
15  feet;  what  should  be  the  depth  of  the  keystone  ?  Give 
depths  by  both  Trautwine's  and  Rankine's  formulas. 

»         j  By  Trautwine's  formula,  depth  of  keystone  =  1.57  ft. 
(     By  Rankine's  formula,  depth  of  keystone  =  1.34  ft. 

(833)  The  span  of  a  segmental  arch  is  38  feet ;  the  rise 
is  12  ft. ;  what  is  the  length  of  the  radius  which  will  touch 
the  soffit  of  the  arch  at  the  springing  lines  and  crown  ? 

Ans.   21.04  ft. 

(834)  The  radius  of  an  arch  is  12  ft.  and  the  rise  8  ft. ; 


RAILROAD   CONSTRUCTION.  1323 

what  should  be  the  thickness  of  the  abutments  at  the  spring 
Hne,  providing  their  height  is  not  more  than  1^  times  the 
width  of  their  base  ?  Ans.  5.2  ft. 

(835)  {a)  What  are  the  essential  ingredients  of  con- 
crete ?  {d)  What  are  the  usual  proportions  of  the  in- 
gredients ?     (c)  How  should  they  be  mixed  ? 

(836)  What  is  the  object  in  making  the  foundation  area 
greater  than  that  required  for  the  superstructure  .'' 

(837)  What  is  the  advantage  of  ramming  concrete  ? 

(838)  What  are  suitable  proportions  of  sand  and  cement 
for  mortar  to  be  used  in  arch  culvert  masonry,  and  how 
should  the  ingredients  be  mixed  ? 

(839)  What  is  the  minimum  tensile  strength  per  square 
inch  of  neat  cement  of  24  hours'  age  allowable  in  arch  cul- 
vert work  ? 

(840)  What  is  the  object  in  pointing  the  joints  of  mason- 
ry?    Describe  the  process. 

(841)  What  are  arch  centers,  their  object,  and  how 
built  ? 

(842)  What  are  striking  or  lowering  wedges,  and  what 
purpose  do  they  serve  ? 

(843)  In  laying  arch  stones,  how  should  the  beds  be 
arranged  ? 

(844)  When  should  the  backing  of  an  arch  be  started  ? 

(845)  At  what  stage  in  the  building  of  an  arch  is  the 
pressure  liable  to  lift  the  crown  ?  When  is  the  pressure 
liable  to  lift  the  haunches  ? 

(84:0)  At  what  angle  to  the  faces  of  an  arch  culvert  are 
wing  walls  usually  built  ? 

(847)  What,  is  a  retaining  wall  ? 

(848)  A  retaining  wall  of  mortar  rubble  10  feet  in  height 
is  required  to  sustain  an  embankment  of  earth  level  with 
its  top;  what  should  be  the  thickness  of  its  base,  the  front 
being  battered  1  inch  to  the  foot  and  the  back  vertical  ? 

Ans.  4  ft. 


1324  RAILROAD   CONSTRUCTION. 

(849)  How  does  inclining  the  base  of  a  retaining  wall 
backwards  affect  its  stability  ? 

(850)  What  effect  is  produced  by  battering  the  back  of 
the  wall  ? 

(851)  In  latitudes  where  deep  freezing  occurs,  what 
measures  should  be  taken  to  withstand  its  effects  ? 

(852)  What  produces  the  effect  of  bulging  in  retaining 
walls  ? 

(853)  Illustrate  by  figure  the  method  of  offsetting  the 
backs  of  retaining  walls  so  as  to  increase  their  base  without 
increasing  their  volume. 

(854)  What  are  surcharged  walls  ? 

(855)  Explain  by  figure  the  angle,  the  slope,  and  the 
prism  of  maximum  pressure. 

(856)  In  determining  the  dimensions  of  a  retaining  wall, 
what  is  the  unit  length  of  section  of  wall  and  backing  used  ? 

Ans.  1  ft. 

(857)  When  the  backing  is  level  with  the  top  of  the 
wall,  at  what  point  of  the  back  of  the  wall  is  the  center  of 
pressure  ? 

(858)  Give  the  formula  for  perpendicular  pressure,  with 
explanatory  figure. 

(859)  What  are  the  forces  which  give  to  a  retaining  wall 
its  stability  ? 

(800)     What  is  meant  by  the  angle  of  wall  friction  ? 

(8G1)  The  height  o  d  (see  Fig.  18)  of  the  retaining  wall 
a  b  d  c  \s\^  ft.  The  thickness  at  the  base  ^  </  is  8  ft. ;  the 
thickness  at  the  top  rt-  ^  is  2.5  ft. ;  the  front  is  battered  1  inch 
to  the  foot,  and  the  base  b  f  oi  the  triangle  b  d  fis  12.73  feet. 
Taking  the  weight  of  the  backing  at  120  pounds  per  cubic 
foot  and  the  weight  of  the  wall  at  154  pounds  per  cubic  foot, 
determine  graphically  to  a  scale  of  4,000  lb.  =  1  in.  the 
resultant  of  the  forces  tending  to  overturn  the  wall  about 
its  toe  f  as  a  fulcrum. 

(862)     What  does  earth  work  embrace  ? 


RAILROAD  CONSTRUCTION 


1325 


Fig.  18. 

(863)  Describe  the  different  sections  formed  by  the 
roadway. 

(864)  What  character  of  work  is  best  performed  by  a 
road  machine  ? 

(865)  What  is  meant  by  the  term  "  lead  "? 

(866)  With  a  lead  of  400  feet  and  wages  at  $1.15  per  day, 
what  would  be  the  cost  per  cubic  yard  to  the  contractor  for 
delivering  earth  at  the  dump,  the  gang  niimbering  25  men, 
with  foreman  at  $2.00  per  day,  water  carrier  at  $0.90  per 
day,  and  allowing  1  pick  to  5  wheelbarrows  and  ^  cent  per 
yard  for  wear  of  tools  and  barrows  ?  Ans.  21.24  cents. 

(867)  With  a  lead  of  700  feet  and  wages  at  $1.20  per  day, 
what  will  be  the  cost  per  cubic  yard  to  the  contractor  to  de- 
liver light  sandy  soil  upon  the  dump,  carts  with  driver  cost- 
ing $1.40  per  day;  foreman  in  charge  of  12  carts,  $2.25  per 
day;  water  carriers,  $1.00  per  day;  dumping  and  spreading, 
1  cent  per  cubic  yard ;  number  of  minutes  actually  employed 
by  shovelers,  420  per  day ;  rate  of  travel  for  carts,  100  feet 
of  lead  per  minute;  time  consumed  in  loading  and  turning 
and  dumping,  4  minutes,  allowing  2  cents  per  cubic  yard 


1326  RAILROAD   CONSTRUCTION. 

for  loosening  soil  and  ^  cent  per  cubic  yard  for  use  and  wear 
of  tools  ?  Ans.  1G.97  cents. 

(868)  Name  the  different  methods  of  hand  drilling. 

(869)  What  special  advantages  have  jumper  drills  over 
churn  drills  ? 

(870)  What  are  percussion  drills  ? 

(871)  In  the  percussion  drill,  how  is  the  rotation   of  the 
drill  effected  ? 

(872)  What  are  the  advantages  of  compressed  air  over 
steam  for  tunnel  work  ? 


RAILROAD  CONSTRUCTION. 

(ARTS.  1503-1592.) 


(873)  At  what  depth  of  cutting  does  it  become  expedient 
to  drive  a  tunnel  ? 

(874)  What  is  the  most  favorable  time  in  the  day  for 
running  tunnel  lines,  and  what  conditions  of  the  atmos- 
phere are  necessary  for  accurate  results  ? 

(875)  What  is  the  object  of  running  the  line  by  fore- 
sights ? 

(876)  What  are  the  usual  methods  employed  in  measuring 
the  surface  line  ? 

(877)  Assuming  60"  F.  as  normal  temperature,  what  is 
the  correct  length  of  a  line  which  measures  89.621  feet,  the 
temperature  being  94°  ?  Ans.   89.641  ft. 

(878)  The  distance  between  two  points  on  a  tunnel  line 
as  measured  on  the  slope  is  89.72  feet;  the  difference  of 
elevation  between  the  extremities  is  11.44  feet;  what  is  the 
horizontal  distance  between  the  extremities  ? 

Ans.   88.986  ft. 

(879)  What  are  standard  dimensions  for  a  single  track 
tunnel  section  ?    what  for  a  double  track  ? 

(880)  In  tunnel  driving,  how  is  the  section  of  the  tunnel 
divided  ?  * 

(881)  Show  by  figure  the  arrangement  of  drill  holes  in 
the  heading  and  bench. 

(882)  What  is  the  usual  order  of  firing  the  holes  ? 

(883)  What  is  the  first  consideration  in  determining  tun- 
nel grades  ?  What  rate  of  grade  will  insure  complete 
drainage  ? 


1328  RAILROAD   CONSTRUCTION. 

(884)  What  is  the  usual  arrangement  of  tunnel  tracks  ? 

(885)  The  elevation  of  the  grade  of  a  station  in  a  tunnel 
is  162.0  feet;  the  height  of  instrument  is  179.3  feet;  the 
height  of  the  tunnel  section  is  24  feet;  what  should  the  rod 
read  when  the  roof  is  at  grade  ?  Ans.   6.7  ft. 

(886)  In  tunnel  work,  what  special  advantage  is  obtained 
by  sinking  shafts  ? 

(887)  Describe  the  usual  arrangement  of  tunnel  tracks 
and  scaffolding  for  loading  excavated  material. 

(888)  Briefly  describe  the  process  of  tunneling  through 
soft  ground. 

(889)  How  is  the  center  line  of  the  tunnel  run  and 
maintained  during  construction  ?    . 

(890)  Describe  the  process  of  plumbing  a  shaft. 

(891)  How  much  pure  air  per  minute  does  a  man  require 
in  order  that  he  may  do  effective  work  ? 

(892)  An  18-inch  air  pipe  conveys  air  from  a  tunnel 
heading  at  a  velocity  of  13  feet  per  second ;  how  many  laborers 
will  it  provide  with  pure  air,  allowing  100  cubic  feet  per  man 
per  minute  ?  Ans.   14  laborers. 

(893)  What  is  an  average  day's  work  for  a  machine  drill 
in  lineal  feet  of  hole  drilled  ? 

(894)  What  are  surface  ditches  ? 

(895)  What  are  cribs,  and  how  are  they  used  in  protection 
work  ? 

(896)  Where  is  stone  paving  usually  employed  in  works 
of  protection  ? 

(897)  A  culvert  crosses  a  railroad  line  at  an  angle  of  75°; 
the  opening  is  three  feet  in  height;  the  covering  flags  and 
the  parapet  each  1  foot  in  height,  and  the  embankment  21 
feet  in  height.  What  should  be  the  distance  from  the  center 
line  to  the  face  of  the  culvert  ?  Ans.  36.06  ft. 

(898)  What  are  borrow  pits  ? 

(899)  How  should  they  be  staked  out  ? 


RAILROAD   CONSTRUCTION. 


1329 


(900)  How  should  they  be  mapped  and  their  contents 
calculated  ? 

(901)  What  are  grade  stakes  ? 

(902)  The  grade  at  a  station  is  118.7  ft. ;  the  height  of 
instrument  is  125.5  ft.;  what  should  the  rod  read  at  the 
station,  for  the  roadway  to  be  at  grade  ?  Ans.   G.8  ft. 

(903)  What  does  the  term  overhaul  signify  ? 

(904)  What  are  the  two  important  factors  in  the  location 
of  a  bridge  ? 

(905)  What  is  the  meaning  of  the  term  skew  as  applied 
to  bridges  ? 

(906)  Describe  a  method  of  making  a  direct  measurement 
of  a  bridge  span  ? 

(907)  Let  A  B  (see  Fig.  19)  be  the  center  line  of  the  pro- 
posed bridge,  and  B  C  the  base  line,  the  length  of 
which  is  421.532  ft.  The  angle  A  is  46°  55';  the  angle  C 
is  43°  22' ;  required,  the 
length  of  A  B. 

Ans.  396.31  ft. 

(908)  What  are  some 
of  the  considerations 
which  determine  the 
number  and  location  of 
the  piers  of  a  bridge  ? 

(909)  When  the  river 
bed  is  of  rock,  or  firm 
sand,  or  clay,  how  are 
pier  foundations  pre- 
pared ? 

(910)  What  are  coffer- 
dams ?  Fio-  «• 

(911)  A  side  of  a  cofferdam  is  40  feet  in  length  and  11 
feet  in  height;  the  water  is  10  feet  in  depth;  {a)  what  is 
the  total  water  pressure  against  the  side  of  the  dam  ?     (b) 


the  dam?  ^^^    (  (a)  17.875  ft. -lb. 


1330  RAILROAD   CONSTRUCTION. 

What  is  the  moment  of  the  water  pressure  about  the  inner 
tee  of  the  dam  ?  j^^^   j  {a)  125,000  lb. 

*  (  (^)  10,471  ft. -lb. 

(912)  If  the  filling  of  the  dam  is  5  feet  in  thickness, 
11  feet  in  height,  and  weighs  130  lb.  per  cu.  ft.,  (a)  what  is 
the  moment  of  resistance  of  which  the  filling  alone  opposes 
to  the  water  pressure  ?     {d)  What  is  the  factor  of  safety  of 

■  (  (^)  1.71. 

(913)  Under  what  conditions  would  you  construct  a  pile 
foundation  ? 

(914)  How  would  you  protect  the  foundation  from  the 
scour  of  the  current  ? 

(915)  What  stone  is  best  suited  to  bridge  foundations  .'' 
(91G)     In   building  bridge  piers,   what  are  the  different 

materials  used  for  backing  ? 

(917)  Under  what  conditions  are  pneumatic  foundations 
employed  ? 

(918)  What  are  tfsi  holes  as  employed  in  foundation 
work,  and  how  are  they  ordinarily  made  ? 

(919)  Describe  the  construction  and  use  of  the  sand 
pump. 

(920)  How  does  the  depth  of  the  foundation  affect  the 
size  of  the  caisson  ? 

(921)  What  is  the  object  in  battering  the  sides  of  a 
caisson  ? 

(922)  How  is   entrance  to  the  caisson  chamber  effected  ? 

(923)  E.xplain  the  working  of  the  air  locks. 

(924)  How  is  the  air  pressure  within  the  caisson  utilized 
in  removing  the  material  excavated  in  sinking  the  caisson  } 

(925)  How  is  the  sinking  of  the  caisson  regulated  ? 

(926)  Describe  the  process  of  sealing  the  caisson. 

(927)  What  is  the  air  pressure  in  the  caisson  at  a  depth 
of  70  feet  below  the  water  surface  .'' 

Ans.   45*38  lb.  per  sq.  ia 


RAILROAD   CONSTRUCTION.  1331 

(928)  Give  the  Engineering  News'  formula  for  pile 
driving. 

(929)  What  are  the  various  methods  employed  in  pile 
driving  ? 

(930)  A  hammer  weighing  3,500  pounds  falls  free  from 
a  height  of  30  feet  upon  the  head  of  a  pile ;  what  is  the  force 
of  the  blow  ?  Ans.   105,000  ft. -lb. 

(931)  When  driving  a  pile,  what  is  the  effect  of  an 
interval  of  rest  between  blows  ? 

(932)  What  effect  have  broomed  pile  heads  upon  the 
striking  force  of  the  hammer  ? 

(933)  What  effect  results  from  driving  piles  with  hammer 
rope  slackened  on  the  drum  ? 

(934)  Describe  pile  shoes  and  hoops,  and  state  their 
object. 

(935)  What  are  some  of  the  effects  of  overdriving  piles  ? 
What  is  the  safe  limit  in  spacing  bearing  piles  ?  What  are 
the  effects  of  overcrowding  ? 

(930)  A  hammer  weighing  3,000  pounds  falls  from  a 
height  of  22  feet;  the  average  penetration  of  the  last  three 
blows  is  \  inch ;  what  is  the  safe  load  in  tons  which  the  pile 
will  support  ?  Ans.   44  tons. 

(937)  A  trestle  bent  contains  three  piles.  In  driving 
them  a  hammer  weighing  3,300  pounds,  falling  from  a 
height  of  35  feet,  produces  the  following  last  penetrations, 
viz.,  first  pile,  J  inch;  second  pile,  |inch;  third  pile,  |  inch; 
required,  the  total  safe  load  of  the  bent  in  tons. 

Ans.   191.77  tons. 

(938)  Into  what  two  general  classes  are  pile-driving 
machines  divided  ? 

(939)  What  are  the  essential  parts  of  a  pile-driving 
machine  ? 

(940)  What  are  sheet  piles  ? 

(941)  What  is  the  prismoidal  formula,  and  what  applica- 
tion is  made  of  it  in  estimating  earth  work  ? 


1332  RAILROAD   CONSTRUCTION. 

(942)  Describe  the  quantity  book. 

(943)  What  are  monthly  estimates;  when  are  they  made, 
and  how  do  they  reach  the  chief  engineer  ? 

(944)  What  are  temporary  allowances  ? 

(945)  What  percentage  of  the  estimate  is  usually  reserved 
by  the  company,  and  what  is  the  object  of  such  a  reserva- 
tion ? 

(946)  What  is  the  final  estimate  ? 


TRACK  WORK, 

(ARTS.  1593-1727.) 


(947)  What  constitutes  a  gooa  tracK  ? 

(948)  Why  is  a  hewn  tie  superior  to  a  sawed  tie  ? 

(949)  Name  the  months  most  favorable  for  cutting  tie 
timber. 

(950)  (a)  What  are  proper  dimensions  for  standard 
gauge  cross-ties  ?  (d)  Where  should  they  be  piled  for  in- 
spection, and  what  are  the  usual  marks  employed  by  a  tie 
inspector  ? 

(951)  (a)  At  what  interval  should  track  centers  be 
placed  ?  (d)  At  what  intervals  should  stakes  for  bedding 
ties  be  placed  ? 

(952)  What  is  an  average  day's  work  in  track  laying  with 
a  machine  ? 

(953)  (a)  How  are  ties  lined  ?     (d)  how  bedded  ? 

(954)  Define  suspended  and  supported  joints. 

(955)  Describe  the  proper  method  of  transferring  rails 
from  car  to  car,  and  of  delivering  them  from  the  car  to  the 
grade. 

(956)  How  may  kinked  rails  be  straightened  ? 

(957)  A  curve  contains  42°;  how  many  29^-ft.  rails  are 
required  to  keep  the  joints  in  proper  position  ? 

Ans.  7  rails. 

(958)  At  a  temperature  of  85°,  an  iron  bar  measures 
30.016  feet;  assuming  normal  temperature  at  60°,  what  is 
the  normal  length  of  the  bar  ?  Ans.  30.011  ft. 

(959)  What  are  expansion  shims,  and  their  objects  ? 


1334  TRACK  WORK. 

(9G0)  What  is  the  proper  mode  of  driving  spikes,  and 
how  should  they  be  arranged  .in  the  tie  ? 

(9G1)     What  is  the  proper  mode  of  gauging  track  ? 

(962)  Describe  the  process  of  lining  track. 

(963)  After  a  new  track  is  laid,  what  are  the  steps  taken 
to  put  it  into  surface  ? 

(9G4)     What  is  subgrade  ? 

(965)  State  some  of  the  methods  for  effecting  the  drain- 
age of  cuttings. 

(966)  Give  sketch  showing  section  of  track  in  earth 
ballast  and  in  rock  ballast. 

(967)  What  is  the  effect  of  straining  track  bolts  ? 

(968)  Describe  the  process  of  putting  new  ties  into  a 
track. 

(969)  How  is  old  track  prepared  for  ballasting  with  stone 
or  gravel  ? 

(970)  What  is  the  proper  method  to  be  employed  in 
raising  track  ? 

(971)  What  is  the  most  effective  form  of  fence  for  fen- 
cing a  railroad  ? 

(972)  What  height  of  fence  is  prescribed  by  law  in  most 
of  the  States  ? 

(973)  What  are  shims  ? 

(974)  What  effect  has  frost  upon  pile  bridges  ? 

(975)  How  are  snow  drifts  prepared  for  the  snow  plow  ? 

(976)  Where  are  snow  fences  required,  and  how  located  ? 

(977)  An  8°  curve  is  425  feet  in  length,  the  gauge  of 
track  is  4  feet  9  inches,  the  width  of  the  rail  head,  2  inches; 
what  is  the  excess  of  length  of  the  outer  rail  over  the  inner 
rail  ?  Ans.  2.91  ft. 

(978)  What  is  the  middle  ordinate  of  a  30-foot  rail  for  a 
6°  curve  ?  Ans.  1^  in. 

(979)  The  middle  ordinate  of  a  50-foot  chord  is  3^  inches; 
what  is  the  degree  of  the  curve  ?  Ans.  5°  36'. 


TRACK  WORK.  VVAo 

(980)  Why  is  it  necessary  to  widen  the  gauge  on  sharp 
curves  ? 

(981)  What  is  the  proper  method  of  lining  curves  ? 

(982)  What  is  the  formula  for  curve  elevation  ? 

(983)  A  curve  is  10°,  and  the  velocity  of  train  is  35  miles 

per  hour;  by  the  formulas  c  =  1.587  V  and  ;//  =  -5-77,  what 

should  be  the  elevation  of  the  outer  rail  of  the  curve  •? 

Ans.   8  in.,  nearly. 

(984)  If  the  elfevation  of  the  outer  rail  of  a  curve  is 
4  inches,  what  should  be  the  length  of  the  elevated  approach  ' 

Ans.  240  ft. 

(985)  What  is  the  object  of  coning  the  treads  of  car 
wheels  ? 

(980)  What  is  a  turnout  ? 

(987)  What  do  you  understand  by  the  number  of  a  frog  ? 

(988)  Name  the  two  classes  of  frogs,  and  describe  them. 

(989)  What  are  crossing  frogs  ? 

(990)  What  is  a  replacing  frog,  and  how  is  it  used  ? 

(991)  Name  the  two  principal  types  of  switches. 

(992)  Describe  the  stub  switch. 

(993)  Describe  the  split  switch. 

(994)  {a)  What  is  a  facing  switch  ?  {d)  a  trailing  switch  ? 

(995)  What  is  a  safety  switch  ? 
(990)  What  is  a  three-throw  switch  ? 

(997)  What  are  derailing  switches  ? 

(998)  What  are  automatic  turnouts  ? 

(999)  What  is  a  Y  track  ? 

(1000)  The  radius  of  the  turnout  curve  from  a  straight 
track  is  002.8  feet,  and  the  gauge  is  4  feet  8.J^  inches;  what 
is  the  frog  number  ?  Ans.  No.  8  frog. 

(1001)  In  a  turnout  from  a  straight  track,  the  number 
of  the  frog  is  0,  the  gauge  of  the  track  is  4  feet  8^  inches; 
what  is  the  radius  ?  Ans.  339  ft.  =  16°  54'  curve. 


1336  TRACK  WORK. 

(1003)  The  degree  of  the  turnout  curve  from  the  straight 
track  is  18°,  the  gauge  is  4  feet  9  inches;  what  is  the  frog 
distance  and  frog  angle  ? 

.         (   Frog  distance  =  55.1  ft. 
I    Frog  angle  =  9°  55'. 

(1003)  The  main  track  is  a  0°  curve,  and  to  reach  a  cer- 
tain warehouse  it  is  necessary  to  use  a  10°  30'  curve  in  the 
opposite  direction  from  that  of  the  main  track;  what  is  the 
required  frog  distance  and  frog  angle,  the  gauge  at  the  track 
being  widened  to  4  feet  9  inches  ? 

.         j    Frog  distance  =  57.5  ft. 
-  i   Frog  angle  =  9°  '29f . 

(1004)  The  main  track  is  a  4°  curve  to  the  right,  and  to 
reach  a  certain  point  it  is  necessary  to  put  in  a  12°  turnout 
curve  to  the  right;  how  far  from  the  P.  C.  of  the  turnout 
curve  shall  we  place  the  head, block,  if  we  allow  5  inches  be- 
tween the  gauge  lines,  the  gauge  being  widened  to  4  feet 
9  inches  ?  '  Ans.  24.5  ft. 

(1005)  If  the  spread  of  the  heel  of  a  No.  9  frog  is  8^  inches, 
what  is  the  distance  from  the  heel  to  the  theoretical  point 
of  frog  ?  Ans.  G  ft.  4|  in. 

(1006)  At  what  distance  from  the  gauge  line  should  a 
guard  rail  be  placed,  when  the  track  is  laid  to  a  close  gauge  ? 

Ans.  If  in. 

(1007)  The  distance  from  the  head  block  of  a  switch  to 
the  last  long  tie  behind  the  frog  is  60  feet ;  the  ties  being 
15  inches  apart,  how  many  switch  ties  are  required  for  the 
switch  ?  Ans.  48. 

(1008)  The  length  of  the  tie  next  the  head  block  is  8  feet 
6  inches,  the  length  of  the  last  long  tie  behind  the  frog  is 
15  feet  3  inches,  the  number  of  switch  ties  is  48;  what  is  the 
amount  to  be  added  to  the  length  of  each  tie  to  give  the 
length  of  the  next  ?  Ans.  1\^  in. 

(1009)  How  do  you  obtain  the  length  of  switch  timbers 
for  a  three-throw  switch  ? 

(1010)  A  three-throw  switch  is  formed  by  two  turnout 


TRACK  WORK.  1337 

curves  at  10°  each ;  what  is  the  angle  of  the  crotch  frog,  the 
gauge  being  4  feet  8^  inches  ?  Ans.  10'  22.8'. 

(1011)  What  are  cross-over  tracks  ? 

(1012)  What  is  the  proper  method  of   lining  detached 
track  ? 

(1013)  When  cutting  steel  rails,  what  precautions  should 
be  taken  ? 

(1014)  At  what  distance  from  the  point  of  danger  should 
danger  signals  be  placed  ? 

(1015)  At  what  distance  from  stations  should  whistling 
posts  be  located  ? 

(1016)  When  repairing  track,  what  precautions  should 
be  taken  to  protect  trains  ? 


RAILROAD  STRUCTURES. 

(ARTS.  1728-1824.) 


(1017)  What  is  the  average  Hfe  of  a  wooden  trestle  ? 

(1018)  Why  are  mathematical  formulas  less  reliable  for 
designing  structures  of  wood  than  structures  of  metal  ? 

(1019)  What  should  be  the  limit  in  height  for  a  pile 
trestle  ? 

(1020)  What  advantage  is  derived  from  piles  driven  at  a 
batter  ? 

(1021)  Under  what  conditions  may  a  3-pile  bent  be 
employed  ? 

(1022)  What  conditions  require  the  splicing  of  piles  ? 

(1023)  Before  ordering  the  material  for  a  pile  bridge, 
what  measures  should  be  taken  to  determine  the  necessary 
length  of  piles  required  ? 

■  (1024)     Name  the  different  methods  of  fastening  caps  to 
piles. 

(1025)  (a)  What  is  the  standard  size  of  mortise  and 
tenon  for  post,  cap,  and  sill  connections  ?  (/;)  What  are 
treenails  ? 

(1026)  What  are  the  special  merits  of  s^/if  caps  f 

(1027)  What  advantages,  besides  stability,  result  from 
proper  foundations  for  trestles  ? 

(1028)  Name  the  several  kinds  of  foundations  employed 
in  trestle  building. 

(1029)  Under  what  conditions  would  you  employ  a 
grillage  foundation  ? 

(1030)  How  are  crib  foundations  constructed,  and  to 
what  situations  are  they  best  suited  ? 


1340  RAILROAD   STRUCTURES. 

(1031)  How  are  foundations  of  broken  stone  prepared  ? 

(1032)  What  are  drip  holes,  and  what  purpose  do  they 
serve  ? 

(1033)  What  are  corbels,  and  their  object  ? 

(1C34)     What  are  separators,  and  their  object  ? 

(1035)     What  are  packing-blocks,  and  their  object  ? 

(103G)  What  two  methods  are  commonly  adopted  to 
fasten  stringers  to  caps  ? 

(1037)  What  are  spreaders  ? 

(1038)  What  are  the  safe  standard  dimensions  tor 
stringers  for  standard  trestles  ? 

(1039)  What  are  jack-stringers,  and  their  object  ? 

j(1040)  (n)  At  what  distance  apart  should  trestle  ties  be 
spaced  ?  (d)  What  advantage  results  from  placing  them 
close  together  ? 

(1041)  What  advantage  results  from  notching  down  the 
ties  over  the  stringers  ? 

(1042)  What  are  guard-rails,  their  object,  and  how  are 
they  fastened  to  the  ties  ? 

(1043)  How  are  guard-rails  spliced  ? 

(1044)  What  modification  should  be  made  in  the  form 
of  the  guard  rail  at  the  connection  of  the  trestle  with  the 
embankment  ? 

(1045)  What  are  sway-braces,  and  their  object  ? 

(1046)  How  is  the  elevation  of  the  outer  rail  effected  on 
curved  trestles  ? 

(1047)  Which  form  of  drift-bolts  has  the  greater  holding 
power,  round  ones  or  square  ones  ? 

(1048)  In  what  two  ways  are  trestles  commonly  connected 
with  embankments  ? 

(1049)  ^Name  some  devices  for  protecting  trestles  against 
fire. 


RAILROAD    STRUCTURES.  1341 

(1050)  Describe  the  usual  method  of  erecting  trestles. 

(1051)  What  is  the  principal  object  of  numbering 
bridges  ? 

(1052)  In  building  pile  trestles,  what  is  the  object  of 
notching  the  caps  over  the  piles  ? 

(1053)  A  spruce  beam  is  10  inches  broad,  12  inches  deep, 
and  18  feet  long;  what  is  its  center  breaking  load  ? 

Ans.  36,000  lb, 

(1054)  When  beams  are  inclined,  what  constitutes  the 
span  ? 

(1055)  A  square  horizontal  beam  of  yellow  pine  is  20  feet 
in  length  between  supports;  what  should  be  its  dimensions 
to  break  under  a  quiescent  center  load  of  50,000  pounds  ? 

Ans.  12f  in.  square,  nearly. 

(1056)  A  beam  having  a  span  of  16  feet  must  safely  bear 
a  center  load  of  16,000  pounds;  what  should  be  the  side  of  a 
square  beam  of  yellow  pine  to  carry  this  center  load  with  a 
factor  of  safety  of  5  ?  Ans.  13:^^  in. 

(1057)  A  horizontal  rectangular  beam  of  spruce  is 
12  inches  in  depth  and  14  feet  between  supports ;  what  should 
be  its  breadth  to  break  under  a  quiescent  center  load  of 
40,000  pounds  ?  Ans.  8f  in. 

(1058)  A  horizontal  rectangular  beam  of  yellow  pine  is 
10  inches  broad ;  the  distance  between  supports  is  16  feet; 
what  should  be  the  depth  of  the  beam  to  break  under  a 
quiescent  center  load  of  24,000  pounds  ?  Ans.  8f  in. 

(1059)  A  rectangular  pillar  of  yellow  pine  is  12  in.  X  12  in. 
in  section,  and  12  feet  high;  what  is  its  safe  load  with  a 
factor  of  safety  of  5  ?  Ans.  91,296  lb. 

(1060)  A  beam  of  long-leaf  yellow  pine  is  subjected  to  a 
shearing  stress  of  30,000  pounds  across  the  grain;  how 
many  square  inches  of  timber  are  required  to  resist  this 
stress  ?  Ans.  60  sq.  in. 

(1061)  A  beam  of  white  oak  is  subjected  to  a  shearing 
stress  across  the  grain  of  40,000  pounds;  how  many  square 
inches  of  timber  are  required  to  sustain  it  ?     Ans.  40  sq.  in. 


1342  RAILROAD    STRUCTURES. 

(10G2)  What  should  be  the  side  of  a  square  horizontal 
beam  of  spruce  which  must  support,  with  a  factor  of  safety 
of  4,  a  uniformly  distributed  transverse  load  of  36,000  pounds, 
and  a  pull  of  20,000  pounds,  the  distance  between  the 
supports  being  12  feet  ?  Ans.  12.  G  in. 

(1063)  What  is  a  king-rod  truss  ? 

(1064)  A  bridge  of  20  feet  span,  and  carrying  an  equiva- 
lent live  and  dead  load  of  6,000  pounds  per  lineal  foot,  is 
carried  by  king-rod  trusses;  what  is  (a)  the  load  upon  each 
king-rod,  and  (d)  what  should  be  the  diameter  of  each,  using 
a  factor  of  safety  of  6  ?  Ans.  {/?)  2f '. 

(1065)  If  the  truss  described  in  the  preceding  example 
carries  a  needle-beam  supporting  the  floor-beams,  what  share 
of  the  total  load  will  the  needle-beam  support  ? 

(1066)  What  advantage  is  gained  by  trussing  the 
needle-beam  ? 

(1067)  What  is  a  queen-rod  truss? 

(1068)  A  load  of  20,000  pounds  travels  from  both  ends 
of  the  straining  bea.m  of  a  queen-rod  truss  towards  the  center; 
Avhat  is  the  total  stress  in  the  beam  ? 

(1069)  A  queen  truss  is  33  feet  in  length  between  sup- 
ports. The  combined  live  and  dead  load  is  equivalent  to 
6,000  pounds  per  lineal  foot  of  bridge.  The  queen-rods 
divide  the  bridge  into  three  equal  parts;  what  is  the  stress 
upon  each  rod  ?  Ans.  33,000  lb. 

(1070)  What  are  water  stations  ? 

(1071)  What  is  their  ordinary  capacity  ? 

(1072)  What  precautions  should  be  taken  against  drouth 
or  impurities  in  water  due  to  floods  ? 

(1073)  What  advantage  is  gained  from  an  elevated  water 
supply  ? 

(1074)  What  is  the  usual  capacity  of  locomotive  tender 
tanks  ? 

(1075)  What  advantage  have  the  individual  stone  pedi- 
ments for  posts  over  woojden  sills  carried  by  continuous 
walls  ? 


RAILROAD   STRUCTURES.  1343 

(1076)  What  is  a  water  column  ? 

(1077)  What  advantage  does  the  water  column  offer  in 
its  adaptation  for  yard  supply  ? 

(1078)  What  are  coaling  stations  ? 

(1079)  What    application    is    made   of    the    link    belt   in 
modern  coaling  stations  ? 

(1080)  What  is  a  turntable  ? 

(1081)  What  is  the  proper  location  for  a  tool  house,  and 
what  are  its  essential  requirements  ? 

(1082)  What  are  the  essential  requirements  of  a  section 
house  ? 


INDEX, 


PAGE 

982 


railroad 


1066 
626 
658 

867 
933 
996 

lOOI 

934 
960 
611 


Abutments  of  bridge 

"  "  stone  arches 

Account,  Tie 
Adjustments  of  transit 
"  Y  level 
Advertising  for   bids   on 

construction     . 
Air  compressor  . 
"    locks 

"    pressure  in  caissons 
"    receiver 
Alinement  of  tunnels 
Alioth  .... 
Aneroid  barometer    . 

"  "  To  determine 

elevations  with  689 

Angle,  Complement  of      .        .        .    602 

"       Exterior,  of  triangle 

"       line 

"      Measure  of 

"      of  frog     . 

'•       "  intersection 

"      Slope 

''      Supplement  of 

"      To  lay  off,  by  chords 

"        "     "      "     '•    its  bearing 

"        "     "      "      "     "    tangents   . 

"        "     "      "     "    latitude    and 

departure  723, 753 


.  605 

631,  762 

.  604 

.  1104 

•  639 
.  677 
.  602 

•  744 

•  747 
751 


Angles,  Alternate  exterior 
"                "          interior 
"       Checking  of,  by  needle 
"        Deflection 
"        Exterior 
"       horizontal.  Measurement  of    631 
"       Interior          .        .        .        .601 
"       Measurement  of,  with  com- 
pass       

"       Opposite  exterior  and  in- 
terior 

'■'  "         interior,    of    tri- 

angle .  .  605 
••  Platting  .  .  .  .741 
"       Vertical         .        ,        .        .638 


602 
601 

633 
642 
601 


610 


602 


Angular  point     .... 

Arch  stones         .... 

Arched  culverts 

Arches,  Stone     .... 

"       Elliptical  or  three  centered 

"        Segmental    . 

"       Semicircular 

Area  of  a  surface 

Areas  determined  by  dividing  plat 

into  trapezoids 

"      determined  by  dividing  plat 

into  triangles 
"      determined  by  double  longi 

tudes      .... 
"     of  similar  figures    . 


B. 


PAGE 
642 


886 
887 
887 
887 
7»4 

716 


727 
603 


PAGE 

Backing  of  bridge  masonry      .        .    991 
"         "  retaining  wall         .      " .    899 

Backsights 610,  630 

Balancing  a  survey    ....    722 

Ballast 1052,  1068 

"        Combination  .        .        .  io68 

"        required  for  mile  of  track    .  1069 

Bank  bent 1208 

"      sills 1062 

Bar  adjustment  of  Y  levei        .        .    660 
Barometer,  Aneroid  ...        .        .    688 
"  "        Klevations  de- 

termined by  689 
Barometric  leveling  .  .  .  656,  688 
Base  line  employed   in   survey  of 

town  sites      .        .        .     736 
"        "     of  townships    .        .        .    696 

Batter  posts 1183 

Beam  compass 776 

"      subjected  to  both  transverse 

and  longitudinal  strains     .  1255 

Beams,  Horizontal     .        .  1247,  1250,  1255 

"        Inclined  ....  1250 

Bearing  piles 1006 

"■       trees.  Location  and  mark- 
ing of  ....    707 
Bearings,  Deduced    ....    634 


Vlll 


INDEX. 


PAGE 
.  €09 
612 
747 
666 
824 


Bearings,  How  to  take      . 

"         Magnetic,  how  corrected 
"         Platting  angles  by   . 

Bench  marks       

"  "      of  railroad  survey 

*'     of  tunnel  ....     946,  948 

Bender,  Rail 1040 

Bents,  Erection  of      .        .        .        .1211 

'•      Framed 1177 

"      for  trestles,  Location  of        .  121 1 

Berme 974 

Bills  of  material.  Proper  forms  of  .  1224 
Boat  spikes         ....  1198,  1200 

Bolts 1199,  1203 

"     Grip  of 1203 

"     Number  of,  for  mile  of  track     1161 
"     Table  of  weights  and  stre'ngths 

of      .....        .  1261 


Bond,  Contractor's     . 

.     868 

Borrow  pits 

•      861,974 

Boundaries,  New 

.     712 

Bracing  of  trestles     . 

•   "95 

"        "       "         Lateral 

.   T196 

"        "        "         Longitudinal     .  1196 

"        "        "         Sway 

•  "95 

Breaking  the  chain    . 

.     616 

Bridge  approaches,  Line  and 

sur- 

face  of 

.   1062 

"       foundations  . 

.     982 

"                  "           Caisson 

.    992 

Pile  . 

.    987 

"       loads 

•  1257 

"       masonry,  Backing  of 

•    991 

"              "          Coping  of 

•    992 

"              "          Stone  suitable  for    991 

"       Measurement  of  span 

of      .    979 

"       numbers 

.  1229 

"       timber    . 

•   1247 

Bridges,  Abutments  of     . 

.    982 

"         Forces  operating  in 

•  1247 

"        Heaved 

.  1081 

"         Location  of 

.    978 

"         Wooden  truss     . 

.  1246 

Bubble  tube  of  Y  level      . 

.     658 

Buildings    .... 

.  1390 

Bulging  of  retaining  walls 

.    901 

C.  PAGE 

Caisson,  Air  locks  of  .        .        .     996 

"  "    pressure  in  .        .        .  loot 

"  Dimensions  of  .  .  .  995 
"  foundations  for  bridges  .  992 
"        Plan  of  ....    997 

"■       Sealing  the  .        .        .  looi 

"        Sinking  the  .        .        .  1000 

Camp  outfit  for  reconnaisance  party    833 


PAGE 

Caps,  Pile 1175 

Car,  Hand   .        .        .        .        .  1149,  1153 
Cart  work.  Cost  of     .        .        .        .    916 

Cattle  guards 883 

Cement,  Qualities  of  .        .        .     890 

Center  cuts  and  fills  ....    856 
Center  line  of  road,  Checking  of      .    976 
Centers  for  arches      ....    893 
"         "    for  tunnel       .        .        .    959 

"       Track 1032 

Chain,  Breaking  the  .        .  .616 

"      Engineer's       ....    613 
"      Errors  in  reading  .        .  614 

Chaining 614 

Check  levels 666 

Checking  angles  by  magnetic  needle  633 
"         the  center  line  .        .        .    976 

Chisels 1151 

Chord  deflection         ....    649 
Chords,  Platting  angles  by       .        .744 

Churn  drills 928 

Circle,  Geometry  of  .        .        .        .    640 
Circles  of  different  diameters,  how 

compared 604 

Claw  bar 1047 

Clearing  ground  for  erection  .  .  1213 
"  right  of  way  .  .  .  860 
"  "  "      Cost  of   .        .    876 

Clinometer 677 

Clips  of  level 658 

Coaling  stations  ....  1281 

Cofferdams,  Construction  of    .        .    983 
Collimation,  Line  of  ...     623 

Colored  topography  ....    806 
Columns  (see  Pillars)        .        .        .  1253 

Compass 605 

"         Beam 776 

"         Defects  and  inaccuracies 

of 608 

"        in  railroad  surveys    .        .    614 
"        Lettering  of        .        .        .    607 

"        levels 608 

"        party.  Method  of  work  of      616 
"  "        Organization  of      .    615 

"         Sights  of       ...        .    606 

"        tripod 608 

"  Use  of  in  preliminary  rail- 
road surveys  .  .  .  822 
Compensation  for  curvature  .  .  846 
Complement  of  an  angle  .  .  .  602 
Compound  curve  ....  640 
Compressed  air  plant  for  tunnels  .  945 
Compressor,  Air  ....  933 
Concrete  for  foundations,  Composi- 
tion of 890 

Contents  of  field,  Calculation  of     .    724 


INDEX. 


IX 


PAGE 

Contour  lines      .... 

673 

"       piap 

673.  778,  781 

Contraction  of  rails   . 

1043 

Contractor,  Duties  of 

866,  1219 

,   I220 

Contractor's  bond 

868 

Coping  of  bridge  pier 

992 

Corbels 

1 186 

Comers  (of  land  survey) 

705 

"        Closing 

709 

"       Double  land  survey    . 

708 

"        Lost  and  obliterated  . 

7'3 

"       Standard       .        .        .        . 

709 

Correction  lines          .        .        .~      . 

696 

Cost,  Comparative,  of  different  rail- 

road lines 

815 

Counter  posts  of  trestle  bent   . 

1196 

Course  (of  a  line)       .        .        .      ' . 

609 

Creosoted  trestles      .        .        .        . 

1216 

Crib  foundations  for  trestle 

1180 

"    work,  Construction  of 

967 

Cribbing,  Protection  by    , 

86s 

Cross-hairs  of  telescope    . 

622 

Crossover  tracks.  Location  of 

"43 

Cross-section  notes.  Form  of    . 

874 

Cross-sectioning         .        .        .        . 

870 

Cross-sections,  Calculation  of 

1017 

Cross-ties 969, 

1029 

Crotch  frog.  Location  of   .        .  1120, 

1142 

Crushing  strength      .... 

1254 

Culvert,  Masonry       .... 

864 

Culverts,  Arched       .... 

885 

"               "       Foundations  for  . 

889 

"         Box 

878 

"          Classification  of 

878 

"          Heaved       .        .        .        . 

1081 

"          how  laid  out  .    . 

970 

"          Open  water 

883 

Tile  for        .        .        .        . 

881 

Curvature,  Compensation  for  . 

846 

"          Degree  of       .        .        . 

642 

"          of  railroad 

828 

Curve  approaches  between  reverse 

curves    

1098 

"      Compound       .... 

640 

"      Degree  of         .... 

643 

"      Difference  in  length  of  inner 

and  outer  rails  of 

1087 

"      Obstructions  in  line  of  .     648 

.837 

"      Point  of 

646 

"      Reversed         .... 

640 

"      Simple 

640 

"     To  lay  out  with  transit 

646 

"          "         "    without  transit    . 

651 

Curved  rails        ..,,.. 

1041 

"      track 

1087 

"          "     Care  of 

1101 

PAGE 

Curved  track.  Effects  of,  upon  loco- 
motives and  car 
wheels 


•    639 

1094,  1099 

.  1093 

775 


851 
762 
832 
1 197 
1098 


Curves 

"       Elevation  of  . 

"       Lining  of 

"       Office 

*'       of  short  radii.  Sub-chords  for 

644,  647 

"       Parabolic 

"       Platting  of 

"       Problems  relating  to 

"       Trestles  on 

"       Turnout,  Elevation  of 

"       Vertical 850 

"       Widening  gauge  of       .        .  1091 

Curving  rails 1088 

"  Table  of  middle  ordin- 

ates  for     .       .        .  1089 
Cuts  (excavation)       .        ,        .     856, 912 

D.  PAGE 

Danger  signals nji 

Datum  line 665 

Declination  of  needle        .        .        .611 

"  "       "      Changes  in    .    612 

Deduced  bearing       ....    634 

Deflected  line 631 

Deflection  angles       ....    642 
"         Tangent  and  chord         .    649 
Degree  of  curve         .        .        ,        .643 
"       "      "     determined   by 

middle  ordinate     653 
"       "  curvature  .        .        .    64a 

Departure 725 

Departures  and  latitudes.  Platting 

by  (see  Latitudes)  .        .        .     723,  753 

Direct  leveling    ....     656,  663 

Distance  across  river.  To  find  .        .    841 

Ditches,  Specifications  for       .        .    862 

"         Surface         ....    966 

Ditching 1052 

Divisions 869 

"        engineer.   Authority  and 

duties  of  .        .        .    869 

Double  centers 630 

"       longitudes     .        .        .  726 

"  "  Areas  found  by    727 

"      track    work,  Specifications 

for 861 

Dowels 1202 

Drag  scraper,  Use  of,  in  excavation    921 

Drainage  of  streets    ....    734 

"         "  track        ....   1052 

"         "  tunnels  ....    950 

Drawing,  Topographical  .  .776 


INDEX. 


PAGE 

Drawings,  Specifications  relating^  to  1213 

Drift  bolts iigg 

"           Holding  power  of   .         .  1201 

"           Table  of  weights  of        .  1201 

Drill  bits 932 

"     Churn 928 

"     Jumper 928 

"     Percussion          ....  929 

Drilling  by  hand,  Cost  of          .        .  928 
"           percussion  drills,  Cost 

of 929 

Drip  holes  for  trestle  mortises         .  1182 

Driver  hammer 993 

E.                              PAGE 
Earth,  how  considered  in  excava- 
tion     862 

Earthwork 912 

Easterly  corner   of  a  survey,   Ex- 
treme          729 

Economy  of  railroads        .        .        .     814 

Elevation 65s 

"         of  curves    .        .        .  1094,  1099 
"         Three  processes  of  deter- 
mining    ....    656 
Embankments,    Connection    of 

trestles  with        .  1207 
'*  Paving  of        .        .    969 

"  Provisions  for  set- 

tling    .        .      861,977 
"  Seeding  and  repair- 

ing of    .        .        .  1074 
Engineer  corps  in  charge  of  con- 
struction .        .        .    869 
"         corps.  Routine  work  of    .    970 
"         Division      ....    869 
"         Resident    ....    869 
Engineer's  chain         ....    613 
"              "    Errors  in  reading     614 
"         transit     .        .        .       .631 

Estimates 1017 

"         Final 1027 

"          Monthly     .        .        .    866,  1025 
"         Preliminary      .        .        .    854 
Excavated  material  of  tunnels,  Re- 
moval of 95a 

Excavation 913 

"  Foundation   .        .        .    862 

"  of  rock,  Cost  of    .        .    926 

"  "  tunnel.  Measurement 

of     .        .        .        .    961 

"  Specifications  for  .     862 

"  Tunnel   .        .        .        .863 

"  "       Cost  of      .        .    964 

Excavator,  Steam       ....    923 

Exhaust  fans 964 


PAGE 

Expansion  and  contraction  of  rails    1043 

"  shims        ....  1044 

Explosives  used  in  tunneling  .        .    948 

Exterior  angles 601 

*'  *'       of  a  triangle    .        .    605 

Extrados  of  an  arch  .        .        .        .886 

P.  PAGE 

Factors  of  safety        .        .        .  1249,  1250 

Fans,  Exhaust 964 

Fence,  Building  of     .        .        .        .  1075 
"       Material  for  one  mile  of       .  1078 

Field  books 654 

"         "      for  land  surveying        ,    709 

"    profiles 842 

Filling  of  retaining  wall   .        .      " .    899 

Fills 856 

Final  grade  lines.  Establishment  of    846 

"      levels  of  railroad  line     .         .     846 

"      location  of  line  .        .        .     843 

Fire  protection  for  trestle         .  1210,  1218 

Focusing  telescope     ....    623 

Floor  system  of  trestles     1186,  1231,  1233, 

1236,  1238,  1240,  1242,  1246 

Footwalks  for  trestles       .        .        .  1210 

Foresight,  To  prolong  a  line  by       .    630 

Foundations  for  arch  culverts         .    889 

"  "  bridges  .        .        .982 

"  "         "        Rock  and 

concrete      98a 
"  "  framed  bents         .  1177 

"  Masonry       .        .        .1178 

"  Pile        .        .        .        .987 

"  Pneumatic  caisson      .    992 

Framed  bents 1177 

Framing,  Specifications  for      .    866,  1215 
Friction  on  retaining  walls      .        .    907 

Frog  angle 1104 

"     crotch.  Location  of  .        .  1120,  1143 

"     distance 11 27 

"     Keyed 1106 

"     number 1104 

"     Plate 1105 

"     point  ......  1 103 

Frogs II03 

"      Crossing 1109 

"      Laying  of,  in  track  .        .  J«39 

"      Replacing         .        .        .        .1110 

"      Spring-rail        .        .        .        .1107 

"      Stiff   ......   1105 

Frontage,  Water       .        .        .        .703 

Frost,  Guard  against         .        .        .901 

a.  PAGE 

Gauge  of  curves.  Widening     .        .  1091 

"       Tide 692 

"      Track 1047 


INDEX. 


XI 


PAGE 

Gauging  track 1047 

Geometry  of  circle     ....    640 
Grade  in  tunnels         ....    955 

"      line 672 

"      Rate  of 672 

"      lines,  Changing  of  .        .    850 

*'         "      Final       .         .        .        .846 

"      stakes        .....     977 

Grades  for  town  sites         .        .        .    734 

Gradients  of  railroads       .         .        .    827 

Grading  road  bed       ....    86i 

Gravel  as  a  destroyer  of  weeds       .  1072 

"      Cost  of    .        .        .        .        .  1070 

"       pits  .....  1070 

Grillage 988,  1179 

Grip  of  bolts 1203 

Grout  and  mortar      ....     865 

Grubbing  right  of  way      .        .      860,  876 

Guard  rails  of  trestle         .        .        .1192 

"  "  turnouts    .        .        .  1102 

"  on  short  curves      .        .  1092 

Guard  stake 646 

Guards,  Cattle 883 

H.  PAGE 

Hammer,  Striking  force  of       .        .  1004 
Handcars    ....        .1149,1153 

"      level 674 

"         "    Use  of  in  reconnaissance    816 
Heading  of  tunnel     .        .        .     946, 948 

Heel  of  frog 1103 

"      "  switch 1102 

Holes,  Drip 1182 

Homologous  sides,  points,  etc.         .    603 

Hoops  for  piles 1006 

Horizontal  angles.  Measurement  of    631 
Hydrographic  surveying  .        .    690 


I. 

Indirect  leveling 
Inspection  of  materials 

"  "   track     . 

"         "  trestles 
Interior  angles    . 
Intersection,  Angle  of 

"  of  tangents 

Intrados  of  an  arch    . 
Iron  details  of  trestles 


PAGE 
656,  682 

.  866 
1 148,  1155 
1218,  1226 

.    601 

•  639 

•  638 
.     886 

.     1198 
"    in  trestles.  Specifications  for      1217 

J.  PAGE 

Jack  stringers 1190 

"     Track 1049 

Jacob's  staff 608 

Jim  Crow 1040 

Joint  ties.  Location  01'  .         .   1036 


PAGE 

Joints  of  arches.  Pointing  of  .  .892 
"      Preservation  of        .        .        .  1212 

"      Stringer 1188 

"      Track 1036 

Jumper  drill 928 

K.  PAGE 

Keystone  of  arch        ....    886 

"         "      "    Depth  of       .        .    887 

King-rod  truss 1257 


Lag  screws 

"         "      Washers  for 
Latitude  of  a  line 

"  "     point    . 

"         Parallels  of 
Latitudes  and  departures 


Lettering  of  compass 

"  "  maps 

Level  cuttings    . 
"      Hand 


PAGE 

.  1203 

.  1205 

•  72s 

•  717 

•  693 

•  717 

Applica- 
tions of, 
to    plat- 
ting    723,  753 
.    607 
.     810 
.    856 
.    674 


"  "     Useof  in  reconnaissance  816 

"      Locke 674 

"      notes 669 

"      party  (railroad  survey)  .     667,  824 

"      surface 655 

"      Y 656 

"      "  Adjustments  of   .        .        .    658 

"      "  Sensibility  of        .        .        .    661 

"      "  Use  and  care  of    .        .        .    661 

Leveling        ...  •        •    6S5 

•'         Barometic    .        .        .      656,  688 

"         Direct 656 

"  Examples  in  .  .  .663 
"  Indirect  .  .  .  656, 68a 
"  Necessary  degree  of  accu- 
racy in  ...  .  669 
"  Sources  of  error  in  .  .  668 
"         Track  .        .        .        .     i«49 

Levels,  Check 666 

Final 846 

"       for  tunnels     ....    960 

"       of  transit        ....     624 

Lighting  of  tunnels    ....    965 

Line,  Angle  ....      631, 762 

"      Deflected 631 

"      Located 762 

"  of  collimation  ....  623 
"  "  preliminary  survey  .  .  76a 
"  "  railroad.  Choice  of  .  .  819 
"       '*         "         Subdivisions  of  .    869 


Xll 


INDEX. 


PAGE 

Line,  Preliminary  and  located,  rela- 


tive  position  of 

.    842 

"      Random 

.    696 

Lines,  Correction 

.    696 

"      of  survey,  How  markec 

I        •    705 

"      Old,  how  retraced  . 

•    709 

"      Spur 

.    826 

Load  on  pile,  Computation  of 

.  1007 

"     Trestle 

.  1007 

Local  influence   . 

.     6a, 

Located  and  preliminary  lines, 

Rela- 

tive  position  of 

.    842 

Location,  Actual 

.     831 

Final  . 

.    843 

"         Paper          .        . 

.    829 

"         Problems  in 

.    832 

Locke  level 

.    674 

Longitude  of  a  line    . 

•     72s 

"              "    point 

•     717 

Longitudes,  Double  . 

.     726 

"                 "       areas  four 

d  by    727 

Lost  comers,  Restoring  of 

•    713 

M.  PAGE 

Machines,  Pile  driving  .  ,  .  1009 
"  Track  laying    .        .        .  1032 

Magnetic  bearings,  how  corrected  612 
"         declination,  Changes  in  .     612 


"         meridian    . 

606,611 

"         needle  * 

.     605 

"         variation   . 

612,  711 

Map.  Definition  of 

•     741 

"     of  a  village 

•      7W 

"      "  final  location 

.      762 

"     railroad      " 

.      766 

Maps,  Contour    . 

673 

,  778,  78' 

"      Lettering  of     . 

.     810 

"      Right  of  way   . 

.     860 

"      Scale  of     . 

.     8<x, 

"      Size  of       .         .         . 

.     8«, 

"      Topographical 

•     792 

Marking  corners  and  lines 

•     705 

Masonry,  Bridge 

•     991 

Culvert 

.     864 

"          First-class 

.     S64 

"         foundations  for  t 

res 

tie 

bents 

.  1178 

"         Specifications  for 

.     863 

Tunnel 

.     863 

Material,  Bills  of 

.    1224 

"         Care  of 

•    "54 

"        required  for  mile  of  track  1158 

Strength  of 

.  1 

247.  1254 

Meandering 

•      703 

Meridian,  Magnetic    . 

606,611 

"         Principal    . 

. 

•     693 

PAGE 

Meridian,  True,  how  determined    .    611 
Middle  ordinate.  Degree  of  curve 

determined  by     653 
"  "         for  curving  rails     1089 

Monthly  estimates  ....  866 
Monuments  (see  Town  sites)  .  .  73^ 
Mortar  and  grout.  Specifications  for  865 
"  for  arch  culverts  .  .  .  892 
Muck,  Removal  of  ...  .  952 
Mud-sills  of  trestle     .        .  .  "79 

N.  PAGE 

Needle,  Checking  angles  by    .        .    633 

"       Declination  of      .        .        .611 

Dip  of    .        .        .        ...    606 

"       Magnetic       ....    605 

Nipping  bar 1046 

Note  books 654 

Notes  and  records.  Preservation  of    655 

"     Compass 619 

"  "         Form  for  keeping    .     619 

"     Field,  from  paper  location     .    830 
"     for  railroad  location,  Platting 

of 766 

"     for  transit  survey,  form  of    .    654 

"     Level 669 

"  "  How  to  keep  and  check  669 
"  of  reconnaissance  .  .  .  816 
"  Topographical  .  .  .  678 
"  "  Working  up  681, 783 
Number  of  frog 1104 

O.  PAGE 

Obstacles  on  curve.  To  avoid  .     648,  837 
Obstructions  in  line  of  curve  .      648,  837 

Office  curves 775 

"  work  of  railroad  survey  .  825 
Old  lines.  Retracing  of  .  .  .  709 
Ordinate,  Middle,  how  used  for  de- 
termining curve  ....  653 
Organization  of  compass  party  .  615 
Outfit,    Camp,    for     reconnaisance 

party 822 

Overhaul 978 

P.  PAGE 

Packing  blocks 1187 

Paper  location.  Field  notes  from     .    830 

"  "         of  line  of  railroad    .     829 

"  "         profile        .        .        .831 

Parabolic  curves        .  .851 

Parallax 610 

Parallel  rulers 762 

Parallels  of  latitude  .  .         .693 

'•         Standard     ....     696 

Passageway  for  road         .        .        .    883 


INDEX. 


xni 


PAGE 

Pavement 865 

Paving  embankments        .        .        .    969 
Percussion  drills         ....    929 

Pile  bents 1168 

"    driving 1002 

"         "        by  direct    pressure  of 

constant  weight  .  1003 
"         "        by    gunpowder    p  i  1  e- 

driver  .  .  .  1004 
"  "  "  hammer  .  .  .  1003 
"         "         "Nasmyth   steam 

driver  .  .  .  1004 
"  "  "  water  jet  .  .  .  1003 
"  "        Cost  of    .         .        .        .  1014 

"         "       Effect  of  broomed  heads 

upon  .....  1005 
"  "        Effect  of   hammer    at- 

tached to  rope  .  .  1005 
"  "  formulas  .  .  .  1002 
"  *'  machines  .  .  .  1009 
"  "  machines,  Land  .  .  1009 
"  "        machines,  Floating      .  loog 

"•  "■  Methods  of  .  .  .  1003 
"  "  record  .  .  .  .1172 
*'  foundations  ....  987 
"  for  trestle  i.ints.  .  .  .  1007 
"    hoops    .        .        .        .  •      .        .  1006 

"    shoes 1005 

•'   trestles,  Loads  upon  .         .  1007 

Piles  acting  as  columns  ■  .        .        .  1008 

"      Bearing 1006 

"     Creosoted 1216 

"      Capping  of  ....  1175 

"     Close    ......  1014 

"     Length  of 1171 

"      Load  on       .....  1007 

"     Sheet 1013 

"      Spacing  of  ....  1006 

"      Specifications  for      .         .    865,  1214 

"     Splicing  of  .        .        .        .  1170 

Pillars,  Strength  of    .        .        .        .  1253 

Plant,  Compressed  air       .        .        .    945 

Platting  angles 741 

"        by  latitudes  and  departures 

723.  753 

"        compass  survey  .        .    620 

"         notes  for  railroad  location    766 

"         topography  in  the  field      .     677 

Plumbing  shafts  ....    962 

Pneumatic  caisson  foundations        ,    99a 

Pocket  book,  Trautwine's         .        .    858 

Point  of  curve 646 

"       frog 1 103 

"        tangent  ....    646 

Pointing  masonry  joints  .        .        .    892 
Polaris   ....  .        .    6ti 


PAGE 

Polar  star 611 

Portals  of  tunnel  ....  959 
Polygons,  Similar  ....  603 
Posts,  Batter,  for  trestles  .        .1183 

"      Township         ....     705 
"      Whistling         .        .        .        .1152 
Power  of  telescope   ■ .        .        .        .    662 
Preliminary  and  located  lines,  Rela- 
tive positions  of         .     842 
"  estimates       .        .        .    854 

"  survey  (see  Reconnais- 

ance)  .  ...    815 

Preservation   of  joints  of  wooden 

trestle 1212 

Pressure,  Air,  in  caissons         .        .  looi 

"         on  retaining  walls    .        .    908 

Principal  meridian     ....    693 

Prismoidal  formula   ....  1018 

Profiles 671 

"       Field 842 

"       Paper  location      .        .        .    831 

Protection  by  cribs    ....    865 

"  work.  Classification  of  .    966 

Public  lands,  Surveying  of      .        .    693 

Pump,  Sand 994 

Q.  PAGE 

Quantities 856 

"  Estimate  of       .        .        .  1017 

Quantity  book  ....  1017,  1022 
Queen-rod  truss  ....  1269 

R.  PAGE 

Rail  bender 1040 

Railroad  location        ....    813 

"  "       Map  of  .        .        .    766 

Railroads,  Economy  of    .        .        .    814 

Rails 1038 

"     Curved 1041 

"     Curving  of         ....  1088 

"     Cutting  of 1150 

"     Difference  in  length  of  inner 

and  outer  ....  1087 
"  Drilling  of  ....  1150 
"  Expansion  and  contraction  of  1043 
"  Handling  of  ...  .  1038 
"  of  different  heights,  how  con- 
nected      1 149 

"     Spiking  of  ....  1045 

*'     Straightening    ....  1039 
"     Weight  of,  for  mile  of  track  .1139 

Random  line 696 

Range  (of  townships)         .        .        .693 

Ranger 969 

Rate  of  a  grade  line  .        .        .        .672 

Receiver,  Air 934 

Reconnaissance 813 


XIV 


INDEX. 


PACK 

Reconnaissance,  Notes  and  records 

of  .        .        .        .816 

"  Use  of  hand  level  in    816 

Referencing  transit  points        .        .    844 

Refuge  bays  for  tresties   .        .        ,  laog 

Residency 869 

Resident  engineer,  Authority  and 

duties  of 870 

Retaining  wall 899 

"  "    Surcharged       .        .    903 

"  "    Theory  of  .         .    905 

Retracing  old  lines     ....     709 

Reversed  curve 640 

Ridge  lines 777 

Right  of  way 859 

"        "       maps     ....    860 

Rise  of  an  arch 886 

Risks 1219 

Road  bed,  Preparation  of  .        .  1031 

"     machine,  Use  of  in  excavation   913 

Roads i2i8 

Rock  excavation         .         .         .      862, 926 

"      foundations  for  bridges  .    982 

"  "  "    trestles  .   1181 

Rod,  High  or  long      .        .        .        .663 

Rods,  Target 662 

Route,  Choice  of         ....    819 
"     Conditions  determining       .     815 

Rubble  walls 898 

Rulers,  Parallel  .        .        .        .762 

S.  PAGE 

Safety  factors     ....  1249,  1250 

"      switches 1116 

Sand  pump 994 

Scale  of  map 809 

Scraper  work.  Cost  of       .         .      919,  921 

Seasoning  of  cross  ties      .         .         .   1030 

Secant  parallel  lines  ....    601 

Section  buildings        ....  1990 

"      dwelling  houses    .        .        .  1292 

"      lines.  Running  .        .    700 

'•      or  mile  posts         .        .        .    859 

"      records 1157 

Sections,  Inspection  of  from  car  or 

engine     ....  1148 

"         of  line  of  railroad       .        .    859 

"        of  townships        .        .        .    693 

Sensibility  of  Y  level         .        .        .661 

Separators  .        .  .        .        .  1187 

Settling  of  embankment.  Provision 

for 861, 977 

Shaft  lining 950 

"  of  tunnel.  Plumbing  .  .  962 
Shafts  for  tunnels  ....  950 
Sheet  piles 1013 


Shimming  of  track 
Shoes  for  piles    . 
Shore  lines  . 
Side  tracks 
Sights  of  compass 
Signals,  Danger 
Signs,  Location  of 
"      Conventional, 
raphy    . 
Similar  polygons 
Similitude,  Ratio  of 
Simple  curve 


used 


PAGE 

.  1080 
.  1005 
78fi,  7<)o 
•  1057 
.  606 
.  1151 
.    1 1 52 


m  topog- 


•     78g 

.         .     603 

.        .     603 

640 

Single  track  work.  Specifications  for  861 
Sliding  of  retaining  walls  .  .  904 
Slope  angles        .    '    .        .        .        .    677 

"     board 674 

"  stakes.  Setting  of  .  .  .  870 
Slopes,  Right  and  left        .        .        .676 

Snow.  Bucking 1084 

"      Clearing  ditches  and  culverts 

of 1082 

"      Clearing  switches  of      .        .  1082 

"      fences 1083 

"  plow,  Preparing  track  for  .  1082 
"      Prevalence  and  effects  of      .   1081 

"      reports 1082 

Soffit  of  an  arch  .         .        .        .886 

Sounding 690 

Span  of  an  arch  ....    886 

"  "  bridges,  how  measured  .  979 
Spandrel  of  an  arch  ....  886 
Specifications   for   grading   and 

bridging         .    860 

"  "      wooden  trestles  1213 

Spikes,  Boat        ....  1198,  1200 

Cut 1198 

"  Number  of,  for  mile  of  track  1160 
"  Pulling  of  ....  1047 
"      Tables  of  sizes  and  weights 

of  .....    TI99 

Spiking  bridge  ties    ....  1046 

"        rails 1045 

Splicing  of  piles          ....  1170 

Split  switches 1115 

Spread  of  frog 1103 

Springers  of  an  arch          .        .        .  886 

Springing  lines  of  an  arch        .         .  886 

Spur  lines 826 

Stadia  measurements        .         .        .  682 

Stakes,  Grade 977 

"       Slope,  setting  of   .         .         .  870 

Standard  parallels     ....  696 

"        trestle  plans       .                .  1230 
Star,  Polar  .        .        .        .        .        .611 

Station,  Most  easterly  or  westerly, 

how  found                  .        .  729 


INDKX. 


XV 


PAGE 
1281 
614 
6.4 
1274 

923 
1004 
991 
967 
1254 
1254 
1247 

1255 
1253 


Stations,  Coaling: 

"         Distance  apart  of 

"         Numbering  of    . 

"         Water  . 
Steam  excavator 
"       pile  driver 
Stone  for  bridge  masonry 
Streams,  Changing  channels  of 
Stren'gth  of  materials,  Crushing 

"  "  "  Shearing 

"  "  "  Transverse 

"  "  wood  in  tension     . 

"  "  wooden  pillars 

Striking  force  of  hammer  of  pile 

driver 1004 

Stringer  joints    . 

Stringers  of  trestle    .        .        .        .1187 

"         Packed        .        .        .        .885 

"         Size  of         ....  iiQo 

Stub  switch iiii 

Sub-chords  for  curves  of  short  radi 

644,  647 
Subdivisions  of  line  of  railroad 

Sub  grade 

Sub-sills  of  trestle 
Sub-station  .... 

Supplement  of  an  angle    . 
Surcharged  walls 
Surface  ditches  .... 


Surfacing  of  track      .        .         .  1048 
Survey,  Balancing  of 

"        Preliminary     (see     Recon 

naissance)         .        ,        .    815 

"        Testing  of    .        .        .        .     720 

Surveying,  Compass  .         .         .    605 

"  Hydrographic        .         .    690 

"  public  lands,  United 

States  system  of  .    693 

"  Railroad  .        .        .    823 

"  Topographical       .     673, 824 

"  Transit    .        .        .        .621 

Surveyor's  compass  ....     605 

Sway-bracing  of  trestles  .        .        .  1195 

Switch,  Derailing       ....  1121 

"        Facing 1116 

"       How  to  lay  out    .        .        .  1133 

"        Lap 1123 

"        Lorenz 11 18 

"        rails IIII 

"        rods IIII 

"        Split  or  point        .        .1111,1115 

"        stand 1113 

"        Stub IIII 

"       Three-throw         .        .        .1119 
"        Throw  of       .        .        .  iioa,  1113 


loss 
1179 
647 
602 

903 

966 
1073 
722 


Switch  ties,  Number  of,  for  given 
switch 

"        ties.  Rule  for  length  of 

"  "    Tamping  of 

"        timbers 

"  "        Three-throw 

"       Trailing 
Switches 

"         Automatic,  for  turnouts 

"         How  used     . 


Safety  . 


"39 
1 140 
1141 
"3) 
1141 
1116 
IIII 
1 124 
"53 
.  1116,  1118 


PAGE 
.  1 141 

•  649 
■  645 
.   646 


Tamping  of  switch  ties     . 
Tangent  and  chord  deflections 
"         distances      .... 
"         Point  of         ...        . 
"        To  swing  to  pass  through 

a  given  point    .        .        .    840 

Tangents,  Intersection  of  .        .     638 

"  Platting  angles  by  .     751 

Tanks,  Water 1278 

Target  rods 662 

Telescope,  Focusing  of     .        .        .    623 

"■  of  transit  .        .        .    622 

"  Power  of  .        .        .        .    66a 

Tensile  strength  of  wood  .        .  1255 

Terminals,  Arrangement  of    .        .   1145 

"  of  railroad      .        .         .    813 

Test  holes 992 

Testing  a  survey        ....    720 
Throw  of  switch         ....  1103 

Throat  of  frog 1103 

Tide  gauges 692 

Tie  account 1066 

Ties,  Bedding 1035 

Cross 1029 

"      Seasoning  .        .        .  1030 

Creosoted 1216 

Directions  for  placing  in  track  1064 
Disposition  of  old      .        .  1066 

Distributing      ....  1034 
Estimating  for  repairs    .        .  1065 

Joint 1036 

Number  of,  for  mile  of  track  .  1159 

Track 1063 

Trestle 1191 

Timber,  Rule   for  measurement  of  1226 
"         Specification  for  .    866,  1213 

'*         used  in  bridges   .  .  1247 

"  "       trestles,  etc..  Speci- 

fications for.        .  1213 
Timt>ering  of  tunnels  .        .    955 

Toe  of  switch iioa 

Tongue  of  frog 1103 


XVI 


INDEX. 


PAGE 

Tool  house i2<)o 

Tools,  Care  of 1153 

"  Trestle  inspector's  .  .  1228 
Topographer's  notes,  Form  of  .  678 
Topographical   drawing    by    level 

contours       .      777,  779 
'*  drawing  by  lines  of 

greatest  slope    777,  786 
"  drawing  by  shades 

from  vertical  light 

777.  788 

"  drawi  ng,  Conven- 

tional signs  used  in    789 
"  drawing    .        .        .    776 

"  '*       Systems  of     777 

"  survey       .        .     673, 824 

"  "       of  town  sites    735 

673 


Topography 


Colored 

Conventional  signs  used 

in         .        .        . 
Platting,  in  the  field 


Township 


"         divisions    . 
"         lines,  how  run    . 
"         posts,    how    placed    and 
marked    . 
Town  sites  and  subdivisions    . 
Track,  Ballasting  of  . 
bolts.  Loose    . 
"      Removal  of  . 
"      Straining  of 
Bridge  approaches  of   . 
Care  and  maintenance  of 
centers    . 
Curved    . 
Drainage  of    . 
gauge 
inspection 
jack 
joints 
laying 

"     machines 
"     outfit    . 
level 


Lining  of 
Old,  work  on 
Raising  of 
Repairs  to 
Shimming  of 
Surfacing 
ties 
Tunnel    . 

Tracks,  Side 
"       Y      .        . 

Track  work,  Fall 


1050, 


1060,  1073. 


1063,  1075 


806 

789 
677 

<593 
694 
696 


705 
733 
1069 
1062 
1062 
J061 
1062 
1058 
1032 
1087 
1052 
1047 
"55 
1049 
X036 
1029 
1032 
1033 
1099 
1150 
io63 
1070 
1079 
1080 
1048,  1073 
1063 
955 
1057 
1126 
1073 


Track  work,  General   instructions 
for       ...        . 
"  in  tunnels 

"  Spring  .... 

"  Summer 

"  Winter  .... 

Transit,  Adjustments  of   . 

"        Care  of  .... 

"        Directions  for  using  . 
"        Engineer's   .... 
"        notes.  Form  of    . 
"        points.  Referencing   . 
Transverse  strength  of  materials   . 
Trautwine's  Pocket  Book 
Traverse  tables  .... 

Trestle,  Connection    of,  with   em- 
bankment 
"        Foot  walks  for 
"       foundations  of  crib  work  . 
*'  "  "  grillage 

"  "  "  loose  rock  . 


masonry 
solid  rock 


1148 
965 
1058 
1063 
1079 
626 
629 
629 
621 
654 
844 
1247 
858 
718 

1207 
1210 
1 180 
1179 
1181 
1 178 
1181 
1 192 


guard  rails   . 

loads      .....  1007 

Protection  of,  against  fire 

1210,  t2t8 
Refuge  bays  for  .  .  .  1209 
Single  track  pile         .        .  1230 

Plan  of 1230 

specifications       ,        .        .  1213 
Standard  double  track  pile, 

Boston  &  Albany  R.R.    .  1238 
Standard  frame,  Oregon  & 

Washington  R.R.     .        .  1240 
Standard     framed,    Cleve- 
land &  Canton  R.R.        .  1235 
Standard  framed,  Ohio  Con- 
necting R.R.     .        .        .  1237 
Standard     framed,    Penn- 
sylvania R.R.  . 
stringers 
Sway-bracing  of 
ties,  Arrangement  of 


Trestles 


Cost  of  . 

Average  life  of    . 
Bracing  of    . 
Classes  of      .        .        . 
Compound  timber 
Creosoted 
Erection  of   . 
Floor  system  of  . 
Framed 

"        Dimensions  of 
Inspection  of 


•  >33ta 

.  1187 
.  1195 
.  1 191 
.  1 163 
1164,  1166 
.  1163 

•  "95 
.  1166 

•  "35 
.  1216 
.  1211 
.  1 186 
.  1166 
.  1246 

i2i8,  1226 


INDEX. 


XVU 


PAGE 

Trestles,  Iron  details  of  .  .  .  1 198 
"         on  curves    ....  1197 

"         Pile 1166 

"         Technical  names  of  parts 

of 1167 

Triangles,  Equal        ....     601 
"         Similar      ....    603 

Triangulation 634 

"  Span  of  bridges  meas- 

ured by    .        .        .    979 

True  meridian 611 

Truss,  King  rod  ....  1257 

"      Queen  rod        ....  1269 

Tunnel,  Alinement  and  levels  for  .  960 
"  Bench  of  .  .  .  946, 948 
"  Centers  of  .  .  .  .  959 
"        Drainage  of  ...    950 

"        driving  .         .        .        .945 

"  "       Methods  of      .        .    946 

"  "        Plant  required  for      945 

"  "       Progress  in      .        .    965 

"       Excavated  material  of,  how- 
removed    ....    952 
"       Excavation  ....    863 
"  "  Cost  of     .        .    964 

"  "  Measurement 

of  .  .  .  961 
"  Explosives  used  in  driving  948 
"  Grade  of  ...  .  955 
"  Heading  of  .  .  ..  946, 948 
"  heading,  drilling,  and 
blasting  .... 
"  Laying  out  surface  line  of 
"  Lighting  of  . 
"  lines,  Curved 
"  masonry 
"  Measuring  line  of 
"  Portals  of  .  .  . 
"        sections 

"       shafts    .... 
'•  "     Plumbing  of 

"        Stationing  of 
"        Timbering  of 
"       tracks.  Care  of    . 
"       Ventilation  of 

Tunnels 

Turning  points   .... 

Turnouts 

"         Automatic 

Turntables  .... 


U.                             PAGE 
United  States  system  of  surveying 
public  lands 693 


946 
935 
965 
941 
863 
938 
959 
944 
950 
962 
941 
955 
955 
963 
935 
66s 
1127 
1124 
1285 


Valley  lines 


PAGE 

•     777 


"           Advantages  of,  for  rail- 
roads   ....  820 
Variation,  Magnetic  .        .         .      612,  711 
Ventilation  of  tunnels       .         .        .  963 

Verniers 625 

Vertical  angles 638 

"         curves 850 

Voussoirs  of  arches   ....  886 

W.  PAGE 

Wales  of  cofferdam    ....    984 

Wall,  Retaining 899 

•'     Rubble 898 

"     Wing  ....      880,  89s 

Washers 1205 

Washouts 1059 

Watchman's  shanty  ....  1292 

Water  checks 667 

"      columns 1280 

"      frontage 703 

"      jet.  Use  of  in  sinking  piles    .  1003 
"      supply,  Source  of   .        .        .  1275 

"      stations 1274 

"      tanks 1278 

Weeds,  Cutting  and  mowing  .        .  1067 
"        Destroyed  by  gravel  .        .  1072 
Wheelbarrow  work.  Cost  of     .        .    914 
Wheeled  scraper.  Use  of  in  excava- 
tion     919 

Whistling  posts.  Location  of  .  .  115a 
Wing  walls  of  culvert        .         .      880,  895 

Wings  of  frog J103 

Witness  trees  for  land  corners  .  713 
Wood,  Strength  of  ...  .  1254 
Wooden  pillars.  Strength  of  .  .  1253 
Work,  Average  daily,  of  a  man  .  1158 
Work  train  service    ....  1155 

Y.  PAGE 

Y  level,  Adjustments  of    .        .        .658 

"        Sensibility  of        .        .        .661 
"       Use  and  care  of    .        .        .    661 

Y  tracks 1126 

Yard  work 1072 

Yards 1145 


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